Nurse practitioners must take an active role in defining and establishing their practices. In many cases, medical and administrative staffs develop the NP Job description. As a result, many NPs are finding themselves in unsatisfactory, often task-oriented roles. This problem is largely due to NPs' inexperience in establishing practices and a lack of documentation of current practices. When developing the NP practice within the National Cancer Institute-Medicine Branch, it was apparent that the nursing literature offered no information on how to establish an NP practice. This article presents guidelines for developing an NP practice and is based on information obtained during the developmental stages of the nurse practitioner practice at the National Cancer Institute-Medicine Branch.