Osogbo metropolis, with the aim of determining the degree of iron deficiency anaemia in the study population. One hundred confirmed anaemic and recently un-transfused patients with haemoglobin concentration level less than 8 g/dL were selected from two major hospitals in Osogbo. Participants were within aged 6 months – 65 years of both sexes. The parameters estimated were haematological indices using automation (Humancount machine). Serum iron and ferritin were also estimated using Atomic Absorption Spectrophotometry, blood film was made for every patient and stained using Leishman technique. Out of 100 anaemic patients who participated in this study; 30 were children while 70 were adults, age group 0-15 and 16-30 had prevalence of 30 and 38 respectively. Based on the parameter analyzed, 73 were diagnosed to be iron deficient with anaemia, remaining 27 were due to other causes of anaemia like sickle cell anaemia as observed. Among the 73 iron deficient patients, 24(32.9%) were males and 49 (67.1%) were females, there were two peaks 26 (35.6%) and 28 (38.4%) in a group 0-15 and 16-30 years respectively, in 73 diagnosed to be iron deficient anaemia, 26 (35.6%) were children and 47 (64.4%) were adults, degrees of iron deficiency anaemia in the study population were 49 (67.1%) moderate and 24 (32.9%) severe. Iron deficiency anaemia is the commonest type of anaemia in the study area; it has prevalence in adult females.