A Nurse Practitioner (NP) is an Advanced Practice Registered Nurse (APRN) who has completed graduate-level education (either a Master of nursing or Doctor of Nursing Practice degree. Nurse Practitioners treat both physical and mental conditions through comprehensive history taking, physical exams, ordering and interpreting diagnostic tests. NPs can then diagnose the disease and then provide appropriate treatment for the patients, including prescribing medications. NPs can serve as a patient's primary health care provider, and see patients of all ages depending on their specialty (family, pediatrics, geriatrics, etc.). The core philosophy of the field is individualized care who focus on patients' conditions as well as the effects of illness on the lives of the patients and their families. NPs make prevention, wellness, and patient education priorities. In addition to health care services, NPs conduct research and are often active in patient advocacy activities. To become licensed/certified to practice, Nurse Practitioners hold national board certification in an area of specialty (such as family, women's health, pediatrics, adult, acute care, etc. and are licensed through the state nursing boards.

According to the International Council of Nurses, an NP/Advanced Practice Nurse is "a registered nurse who has acquired the expert knowledge base, complex decision-making skills and clinical competencies for expanded practice, the characteristics of which would be determined by the context in which s/he is credentialed to practice.

Nurse Practitioners can be educated and nationally certified in areas of Family Health (FNP), 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 (FNP, ACNP, ANP, PNP or ANP) Emergency (as FNP or ACNP), Occupational Health (as ANP or FNP), etc.