A practice profile is a compilation of information allowing definition and evaluation of any of several parameters of health-care delivery. Prerequisites for development of profiles presented in this report include: suitable classification of health problems; patient demographic data; identification of individual and groups of health-care providers; and definition of the practice or study population. Details are given for two profiles: the assigned patient and the diagnostic workload profiles. Single profiles are purely descriptive but, when evaluated by appropriate peer comparison, may form the basis for a more dynamic process--that of improvement and change. Possible applications of practice profiles are discussed.