BACKGROUND: Despite the proven benefits conferred by early human immunodeficiency virus (HIV) diagnosis and presentation to care, delays in HIV medical care are common; these delays are not fully understood, especially in the southern United States. METHODS: We evaluated the extent of, and characteristics associated with, delayed presentation to HIV care among 1,209 patients at an HIV/AIDS Outpatient Clinic in Birmingham, Alabama between 1996 and 2005. RESULTS: Two out of five (41.2%) patients first engaged care only after they had progressed to CDC-defined AIDS. Among these, 53.6% were diagnosed with HIV in the year preceding entry to care. Recent presentation (2002 - 2005), male sex, age ≥25, Medicare or Medicaid insurance coverage, and presentation within six months of HIV diagnosis were independently associated with initiating care after progression to AIDS. CONCLUSIONS: A high proportion of patients entered clinical care after experiencing substantial disease progression. Interventions that effectively improve the timing of HIV diagnosis and presentation to care are needed. Copyright © 2006 by The Southern Medical Association.