This study was conducted to evaluate the influence of some water quality parameters on the aquatic insects of a rainforest stream in Nnamdi Azikiwe University, Nigeria. Sampling of the stream and aquatic insects was conducted weekly in the wet season, from May through June, 2013 in three stations. The results showed that the pH of all sampling stations was neutral, dissolved oxygen was highest at station 2 (12.93±0.19) and station 3 recorded the highest conductivity, turbidity and TDS. Analysis of variance showed that there was a significant difference in the physico-chemical properties between sampling stations. The insects’ abundance seems to be influenced by substrate, physiological and morphological adaptation, current velocity and turbidity. The physico-chemical properties and Margalef index of water quality shows that the quality of a water body has a role to play in the abundance, diversity and distribution of aquatic insect.