Objective:To investigate the malaria parasitemia,CD4+ cell counts and some haematological indices amongHIV-malaria co-infected adult patients with highly active antiretroviral therapy (HAART).Methods:A total of342 adultHIV positive subjects were recruited at the consultant outpatientHIV/AIDS clinic,University ofBeninTeachingHospital,BeninCity,Nigeria between June2011 toNovember2011.Blood samples were taken for malaria parasite count,CD4+ cell count and other haematological counts.Results:Out of the342 adultHIV positive subjects a total of254 patients (74.3%) were found to have malaria parasitemia.The incidence of malaria parasitemia increased with advancing clinical stage ofHIV infection and this was statistically significant (P=0.002).There was no statistical significance when gender was compared with the HIV-malaria status (P>0.05).Of the254 co-infected patients,134 (52.8%) had high parasitemia (>1.25×109/L).Sixty patients were found to be hyperparasitemic (>2.5 parasites/L).There was a significant association betweenCD4+ cell count and having significant parasitemia (P <0.0001). About half (50.8%) of co-infected patients hadCD4+ cell count≤200/μL, and majority (44.9%) of this population also had significant parasitemia.Anaemia and thrombocytopenia were not significantly associated withHIV-malaria co-infection (P>0.05).Conclusions:The prevalence of parasitemia is high among theHIV/AIDS infected patients.