Hitherto, studies on highly active antiretroviral therapy (HAART) initiation have shown partly inconsistent results. Our study investigated the clinical course and course of immune status after HAART initiation at CD4-cell-count/μl of treated patients between 250 and 349 (group 1), compared to 350-449 (group 2), on the basis of the cohort of the Competence Network for HIV/AIDS (KompNet cohort).