Published epidemiologic data regarding dermatologic practice may no longer be current. The National Ambulatory Medical Care Survey conducted in 1990 provides a comprehensive assessment of ambulatory medical practice including patient demographics, chief and secondary complaints, diagnoses, and drug treatments prescribed. Many specialties including dermatology were represented in the sampling technique. The database was reviewed for descriptive aspects of visits to dermatologists surveyed. Using standardized weighting techniques, we estimated the total number of physician visits. Dermatologists had an estimated 24.0 million patient encounters in 1990. Dermatologists treated a disproportionately large number of female and younger patients. After adjusting for their proportion of the population, Asians and Whites had greater numbers of dermatologic encounters than Blacks and Native Americans. Patients had two or more complaints 27.2% of the time, and received two or more diagnoses 28.9% of the time. The most common complaints accounting for 49.7% of visits included "pimples," "rash," "discoloration," "skin lesion," "wart," and "skin growth." The most common diagnoses, accounting for 52.7% of all encounters, were acne, keratosis, wart, dermatitis or eczema, benign neoplasm, and malignant neoplasm. This paper presents demographic information, chief and secondary complaints, and chief and secondary diagnoses of patients visiting dermatologists in the United States in 1990. Whites and Asian or Pacific Islanders have increased utilization of services compared with Blacks and Native Americans or Eskimos; this disparity correlates with median family income.