Harmonia octomaculata (Fabricius, 1781) was studied in the laboratory at a temperature of 21.4 to 30.3oC and humidity 74 to 77 percent using Brevicoryne brassicae and Aphis gossypii as prey to observe the biological interaction. At 30.7oC and 77 percent RH, the ladybird beetle completes its life cycle in 18.67 +/- 1.09 days, the female laid an average of 18.91 +/- 1.02 eggs/day with a hatching rate of 87 percent, the longevity of adult Harmonia oclomaculata was 32.22 +/- 1.22 days and at 21.4oC and 74 percent RH, its life cycle is 26.73 +/- 0.91 days, the female laid on an average of 12.07 +/- 1.02 eggs/day with a hatching rate of 70.26 percent, and the longevity of adults was 40.34 +/- 1.89 days. Fourth instar larvae and adults consumed aphids more than did other instar larvae. Two types of food were made available (Brevicoryne brassicae and Aphis gossypii). Both larvae and adults preferred to feed on Brevicoryne brassicae more than Aphis gossypii.