OBJECTIVES: Describe US treatment experience trends, shifts in employment status, insurance, and CD4 counts of HIV/AIDS patients since the introduction of highly active antiretroviral therapy (HAART) in 1996. METHODS: HIV-infected patients (n=3203) treated at US clinics from 1996-2004 as part of the HIV Insight database* were studied. Longitudinal patient records were analyzed to track the changing distribution of antiretroviral treatment experience by year. Patients having at least six months of follow-up and enrollment in the reporting year were classified into four treatment experience groups: Nucleoside Reverse Transcriptase Inhibitors (NRTI), Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTI), Protease Inhibitor (PI), and 3-class experience. Demographic shifts were observed for: employment and disability status, and primary insurance type. CD4 counts were examined by treatment experience level. RESULTS: Of the 3203 patients with active enrollment, 2552 were treated. Average follow-up was 3.84 and 4.33 years, respectively. The percentage of patients with treatment experience increased substantially in all 4 groups (1996-2004): NRTI (48%, 98%), NNRTI (4%, 67%), PI (25%, 63%), 3-class (<1%, 36%). The percentage of patients working (part/full-time) increased from 49% to 62% from 1996 to 2004. The percentage of disabled patients decreased from 22% to 15%. Primary insurance coverage for treated patients was distributed as follows (1996-2004): Private insurance (50%, 60%), Medicare (10%, 7.4%), Medicaid (30%, 20%), AIDS Drug Assistance Programs (ADAP) (2.7%, 5.0%), and Other (7.5%, 8.4%). Lower CD4 counts correspond with more treatment experienced patients. CONCLUSIONS: While increased use of HAART therapy corresponds with better employment status and increased private insurance, patients who have more treatment experience have lower CD4 counts, signaling a need for more effective treatment options. *Includes data from the CDC's HIV Outpatient Study, and other US HIV care-sites funded by Cerner Corporation. The findings and conclusions are the authors' and don't represent the views of the CDC/US DHHS.