Anaemia is a common complication of the HIV infection. To understand the mechanism of HIV associated anaemia and to suggest a consequent therapeutic approach in adults in Mali, we undertook a prospective case/control study in two services of reference with essentially adults recruitment in Bamako. We studied the frequency, the risk factors and the prognosis value of this complication in 133 patients with HIV infection matched to 133 others non HIV infected. The average age of our patients was 36.08 +/- 8.80 years (age range: 19 to 66 years). The frequency of anaemia was significantly higher in patients with HIV infection compared to the controls (78.9% vs. 51.9%; OR = 2.46; 95% CI [1.56-3.92]). Anaemia was more frequent in women than in men (p = 0.00003). A significant association between anaemia and thrombopenia or lymphopenia was observed only in patients with HIV infection. The severity of anemia was positively associated with the HIV2 infection and the progression of the HIV disease. Mortality was more frequently associated to the anaemia (p < 10(-5)) in patients infected by HIV. These findings suggest that bone marrow depression leading to a decreased red blood cells production is the main mechanism of HIV associated anaemia in adult in Mali. Therefore, without evidence of a best cost-effectiveness ratio of a human recombinant erythropoietin treatment in the context of countries with a low income, the therapy of this haematological complication must be an emergency focusing on red blood cells transfusions.