The practice of medicine in the United States is regulated almost entirely at the state level. Each state has its own set of laws, typically consolidated in a statute called a medical practice act, that governs who can practice medicine, how they must behave, and what happens when they fall short. These laws vary meaningfully from state to state, covering everything from licensing requirements and malpractice liability to informed consent standards and whether a corporation can employ a doctor.
The Medical Practice Act
Every state has a medical practice act, and it is the single most important piece of legislation governing physicians in that jurisdiction. This statute creates the state medical board, defines what counts as practicing medicine, sets licensing requirements, and outlines what constitutes unprofessional conduct. The medical board then interprets and enforces the act on a day-to-day basis.
State medical boards license physicians, investigate complaints, and discipline those who violate the act. Their overriding mission is public protection: ensuring only qualified physicians are licensed and that they maintain a high standard of care. When a board receives a complaint and has reason to believe a physician violated the medical practice act, it has the power to investigate, hold hearings, and impose discipline up to and including license revocation.
While the specific definitions of unprofessional conduct vary by state, common examples include physical abuse of a patient, inadequate record keeping, failure to recognize or act on common symptoms, prescribing drugs in excessive amounts without legitimate reason, and impaired ability to practice due to addiction.
Licensing Requirements
All states require physicians to hold an MD or DO degree (or its international equivalent, such as an MBBS). Most U.S. medical schools award these degrees after a four-year post-baccalaureate program. Beyond the degree itself, every state medical board requires candidates to complete at least one year of postgraduate residency training before they can receive a full, unrestricted license. Some states require two or three years.
Candidates must also pass a comprehensive national licensing examination that tests their knowledge of health and disease management. They submit proof of education and training, provide their full work history, and disclose information that could affect their fitness to practice, including health conditions, malpractice judgments or settlements, and criminal convictions. Many boards also conduct criminal background checks. Every state evaluates what it calls the physical, mental, and moral fitness of applicants.
Once licensed, physicians must reregister periodically to maintain active status. During reregistration, they demonstrate that they have maintained acceptable standards of ethics and practice and have not engaged in improper conduct. This ongoing oversight is a core function of state law, not just a one-time gate.
Practicing Across State Lines
Because each license is state-specific, a physician licensed in one state cannot simply practice in another. The Interstate Medical Licensure Compact offers a voluntary, expedited pathway for qualified physicians who want to practice in multiple states. As of early 2026, 43 states and 2 U.S. territories participate in the Compact, with Alaska and Massachusetts having introduced legislation to join. The Compact does not replace individual state licenses. Instead, it streamlines the application process so physicians can obtain additional state licenses faster.
Scope of Practice Laws
State laws don’t just regulate physicians. They also define what other healthcare professionals, particularly nurse practitioners and physician assistants, can and cannot do. These scope of practice laws directly shape how medical teams function and who needs physician oversight.
Only 27 states and the District of Columbia allow nurse practitioners full practice authority, meaning they can deliver care to patients without any restrictions or required physician involvement. In the remaining states, nurse practitioners must either have a formal collaborative agreement with a physician (sometimes called “reduced” scope) or practice under direct physician supervision (“restricted” scope). For example, Arizona and Washington grant full practice authority, New Jersey and Pennsylvania require collaboration, and Texas requires supervision. These distinctions matter for patients in terms of who they can see and how quickly they can access care, especially in rural areas.
Medical Malpractice Statutes
Every state has its own medical malpractice laws, and the differences between them are significant. One of the biggest variables is the statute of limitations: the window of time you have to file a claim after being injured. Some states give you as little as one year. Kentucky, Louisiana, and Ohio all set one-year deadlines. Maryland allows up to five years from the date of injury or three years from when the injury was discovered, whichever comes first.
States also differ on whether they cap the amount of money a patient can recover. California’s Medical Injury Compensation Reform Act, originally passed in 1975, capped non-economic damages (pain and suffering, permanent disability, disfigurement) at $250,000. California voters approved an increase to that cap in 2022. Other states have their own caps or no caps at all, which makes the state where the malpractice occurred a critical factor in any claim.
Informed Consent Standards
Before performing a procedure or starting treatment, physicians are legally required to obtain informed consent. But the legal standard for what “informed” means varies by state, and the difference is not trivial.
Most states historically followed what’s called the community standard (sometimes called the “reasonable physician” standard). Under this approach, a physician must disclose whatever information other physicians in the same community would typically share with patients. Several states have moved to a “reasonable patient” standard, which asks a different question: what would a reasonable person in the patient’s position want to know before making a decision? This standard generally requires more disclosure, because it focuses on what matters to the patient rather than what doctors customarily say. The reasonable patient standard is spreading but is not yet universal. Even in states that still use the physician-centered approach, the line between the two standards has blurred over time.
Corporate Practice of Medicine Doctrine
Many states have laws that prevent corporations from directly employing physicians or controlling medical decision-making. This legal principle, known as the corporate practice of medicine doctrine, is based on the idea that medical judgment should be free from business pressure. Under strict versions of this doctrine, a business entity cannot hire physicians to practice their licensed professions unless the legislature has specifically authorized it.
The doctrine exists in some form in the majority of states, but enforcement varies widely. States like Colorado, Illinois, Georgia, Maryland, Oregon, Tennessee, and Washington enforce it strictly with no nonprofit exceptions. Other states, including California, Texas, New York, Ohio, and many more, have the doctrine on the books but allow various exceptions, such as permitting hospitals, universities, or certain nonprofit organizations to employ physicians. A handful of states have no such doctrine at all. This patchwork is one reason healthcare companies structure themselves differently depending on which states they operate in, often using management services organizations or similar arrangements to stay within the law.
Mandatory Reporting Obligations
State laws impose specific reporting duties on practicing physicians. Every state requires physicians to report suspected child abuse, and nearly all require reporting suspected elder abuse. Physicians are also required to report certain infectious diseases to public health authorities, though the exact list of reportable diseases varies by state. Some states mandate reporting of gunshot wounds, domestic violence injuries, or specific conditions like epilepsy that may affect a patient’s ability to drive safely. Failing to report when required can result in disciplinary action, fines, or even criminal penalties depending on the jurisdiction.
Health Privacy Laws Beyond Federal Rules
Federal law (HIPAA) sets a baseline for how patient health information must be protected, but states are free to pass stricter rules. Several have done so. California, for instance, has its own medical privacy laws that impose additional restrictions on how health data can be shared. Some states have enacted stronger protections for specific categories of information, such as mental health records, substance abuse treatment records, HIV status, or reproductive health data. When state law is more protective than federal law, the state law controls. This means physicians and their staff must comply with whichever standard is stricter, which can vary depending on the type of information and where the practice is located.
Telemedicine Regulations
Telemedicine has its own layer of state-specific regulation. Most states require that a physician be licensed in the state where the patient is physically located at the time of the visit, not where the doctor is sitting. States set their own rules for what types of visits can happen virtually, whether an initial in-person visit is required before telehealth follow-ups, and which technologies are acceptable. Some states have specific prescribing restrictions for telemedicine encounters, particularly for controlled substances. The Interstate Medical Licensure Compact has eased some of the burden for physicians who want to see patients across state lines, but the underlying requirement of holding a valid license in each state remains.