Malaria is a major cause of morbidity and mortality in developing countries, accounting for an estimated of 300 to 500 million morbid episodes and 2 to 3 million death per year worldwide. The aim of the study is to determine severity and prevalence of malaria infection and effect of anti-malaria drugs on gender differences using haematological parameters. 202 confirmed malaria infected patients were recruited for the study between the ages of 15 – 64 years of both sexes at the general outpatient clinic of the Federal Medical Centre, Ido-Ekiti, Ekiti State, Nigeria. 4 ml of blood sample was collected twice from the same patient before and after taking anti-malaria drug into di-potassium ethylenediaminetetraacetic acid (K2EDTA) vacuitaner bottles for haematological analysis using haematology analyzer. Malaria parasite detection, malaria parasite count and malaria parasite species identification were also carried out. Out of the 202 malaria infected patients 129 (63.9%) were males and 73 (36.1%) were females. Mean+ SD of RBC, HB, PCV, MCV and MCHC in male were lower compared to female in pre and post anti malaria drug treatment; however, in control subjects mean+ SD of RBC, HB, PCV, MCV and MCHC in male were higher compared to female, the comparism shows significant difference (P<0.05). Severity and prevalence of malaria infection is more observed in male compared to female these might be as a result of different exposure to malaria vector.

malaria parasite, gender, anti-malaria drug