Patient referral from generalists to specialists is a critical clinic care process that has received relatively little scrutiny, especially in academic settings. This study describes the frequency with which patients enrolled in a prepaid health plan were referred to specialists by general internal medicine faculty members, general internal medicine track residents, and other internal medicine residents; the types of clinicians they were referred to; and the types of diagnoses with which they presented to their primary care physicians. Requested referrals for all 2,113 enrolled prepaid health plan patients during a 1-year period (1992-1993) were identified by computer search of the practice's administrative database. The plan was a full-risk contract without carve-out benefits. We assessed the referral request rate for the practice and the mean referral rate per physician. We also determined the percentage of patients with diagnoses based on the International Classification of Diseases, 9th revision, who were referred to specialists. The practice's referral request rate per 100 patient office visits for all referral types was 19.8. Primary care track residents referred at a higher rate than did nonprimary care track residents (mean 23.7 vs. 12.1; P < .001). The highest referral rate (2.0/100 visits) was to dermatology. Almost as many (1.7/100 visits) referrals were to other "expert" generalists within the practice. The condition most frequently associated with referral to a specialist was depression (42%). Most referrals were associated with common ambulatory care diagnoses that are often considered to be within the scope of generalist practice. To improve medical education about referrals, a better understanding of when and why faculty and trainees refer and don't refer is needed, so that better models for appropriate referral can be developed.