Background : The prevalence of anemia in HIV/ AIDS patients is high, with a multitude of possible etiologies; autoimmune hemolytic anemia (AIHA) in HIV/AIDS patients has been associated with a poor prognosis when treated with red cell transfusion. Our aim was to demonstrate the frequency of AIHA in a cohort of adult Nigerian HIV/AIDS patients and to see if the presence or not of AIHA is related to the severity of the disease with regards to the CD4 counts and the presence or absence of opportunistic infections. Method : Ninety- eight adult patients with HIV infection were screened for the presence of AIHA using the packed cell volume (PCV), direct antiglobulin test (DAT) and reticulocyte count (RC). Results : The frequency of AIHA was 3.06%, 36.74% of our study population were anemic; 11.22% had a positive DAT. Mean RC was 2.22 +/- 0.90 for all the patients. There was no statistically significant difference in the PCV of patients that had positive and negative DAT. There was no correlation between the presence of AIHA, use of ART, presence of opportunistic infections or CD4 counts. Conclusion : We conclude that in spite of the low frequency of AIHA in HIV/AIDS patients, the fact that most patients will respond to standard treatment makes it imperative to screen HIV/AIDS patients with anemia for the presence of AIHA. Again since HIV/AIDS patients with AIHA may have a fatal reaction to red cell transfusion, we suggest that anemic patients with HIV/AIDS in non-emergency situations be screened for the presence of AIHA before receiving red cell transfusions when indicated.