The pulse beetle, Callosobruchus maculatus (F) (Coleoptera: Bruchidae), is a worldwide insect pest that infests pulses in the fields and storages. Laboratory experiment was conducted to study the biology and morphometry of C. maculatus under the effect of three different temperature degrees (25, 30, 35 ̊C) and 65 % related humidity. The life cycle consisted of egg, four larval instars (L1, L2, L3 and L4), pupa and adult. The eggs hatched in 6-7, 2-4 and 4-5 days, and the larval duration varied from 15-19, 10-14 and 10-14 days at 25, 30 and 35 ̊C respectively. The morphometric measurements showed that the average length and breadth of egg were 0.54 mm and 0.13 mm respectively. The mean length and breadth of L1, L2, L3 and L4 were 0.68, 1.26, 2.30, 3.58 mm and 0.30, 0.80, 1.29, 1.95 mm respectively. The average length of pupa was 4.30 mm and breadth was 2.27 mm respectively. The average length and breadth of adult was 3.57 mm and 2.10 mm respectively. The life cycle took 30-37, 19-26 and 20-27 days for completion at 25, 30 and 35 ̊C and constant relative humidity. Which concluded that the standard optimum temperature for C. maculatus fitness lie between the range of 30-35⁰C and a relatively high humidity of 65 percent.