Nurse Practitioners treat both physical and mental conditions through comprehensive history taking, physical exams, physical therapy, and ordering tests and therapies for patients within their scope of practice. NPs can serve as a patient's primary health care provider, and see patients of all ages depending on their designated scope of practice.

In the United States, NPs are licensed by the state in which they practice, and have a national board certification (usually through the American Nurses Credentialing Center, American Academy of Nurse Practitioners or the National Certification Corporation). Nurse Practitioners can be trained and nationally board certified in areas of FNP (Family Nurse Practitioner), Pediatrics, including Pediatric Acute/Chronic Care, Pediatric Critical Care, Pediatric Oncology and general Pediatrics (PNP), Neonatology (NNP), Gerontology (GNP), Women's Health (WHNP), Psychiatry & Mental Health (PMHNP), Acute Care (ACNP), Adult Health (ANP), Oncology (ONP), Emergency Medicine (as FNP or ACNP), Occupational Health (as ANP), etc.

In the United States, because the profession is state-regulated, care provided by NPs varies widely. In many states, nurse practitioners work independently and autonomously of physicians while, in other states, a collaborative agreement with a physician is required for practice. The extent of this collaborative agreement, and the role, duties, tasks, medical treatments, pharmacologic prescriptions, etc. it affords an NP to perform and prescribe again varies widely amongst states of licensure. In the states where a collaborative agreement is required, there is no evidence that such legislation either promotes patient safety or positive health outcomes; for this reason there is increasing momentum to remove these types of barriers to autonomous NP practice.

A nurse practitioner's job may include the following:

NPs practice in all U.S. states. The institutions in which they work may include:

To be licensed as a Nurse Practitioner, the candidate must first complete the education and training necessary to be a registered nurse, then go on to complete a graduate-level nurse practitioner program (some of which also require an additional residency), and then the candidate must pass a national board certification in their area of specialty. Registered nurses initially trained at the associate degree or diploma level must first complete a Bachelor of Science in Nursing (BSN) or enter various programs offering an ADN-to-MN/MSN bridge program, some of which award the bachelor's degree while completing the requirements for the master's.

While not every state includes specific language requiring a master's degree for NPs, the majority of states do require a master's degree, post-master's certificate or a doctoral degree. Further, the current nurse practitioner programs offered by all universities and colleges are at the master's, post-master's, or doctoral level. The current plan is that all advanced practice nurse programs will require a Doctor of Nursing Practice (DNP) degree by 2015 thus effectively eliminating the MN or the MSN as an entry to practice degree. Lastly, all states require national board certification for nurse practitioners before they are permitted to practice and the two biggest certifying bodies, the American Nurses Credentialing Center (ANCC) and the American Academy of Nurse Practitioners (AANP), do require applicants to hold a master's degree, post-master's certificate, or doctoral degree to be eligible to test for certification.

The variety of educational paths for NPs is a result of the history of the field. The first Nurse Practitioner program was created by a nurse educator, Loretta Ford, EdD, RN, PNP and a physician, Henry Silver, MD, in 1965 at the University of Colorado as a non-degree certificate program. This program trained experienced Registered Nurses for their new advanced nursing roles as Pediatric Nurse Practitioners. In the late 1960s into the 1970s, continued predictions of a primary-care physician shortage increased funding and attendance in various certificate-based nurse practitioner programs. Then, during the 1980s Nurse Practitioner educational requirements were transitioned into graduate-level master's degree programs. Subsequently the national certifying organizations and state licencing boards began to require a master's degree for NP practice. However, already established NPs with certificate-based education were grandfathered in. Once again there are changes presently in the field, and by 2015 all new NPs will need to be trained at the doctorate level as a Doctor of Nursing Practice. Once again already established NPs with lesser education will be grandfathered in.

After completing the education program, the candidate must be licensed by the state in which he or she plans to practice. The state boards of nursing regulate nurse practitioners and each state has its own licensing and certification criteria. In general, the criteria include completion of a graduate degree in nursing and board certification by an accrediting body (ANCC, AANP). The license period varies by state; some require biennial relicensing, others require triennial.

NPs can pursue additional specialty certification through several organizations, including the following: