Sagar Lake is located in the centre of Sagar city in Madhya Pradesh. This lake is surrounded by agricultural fields, industries, hospital, bus stand and slums. The waste from the industries and surrounding localities is directly discarded into the lake. To evaluate the water quality of this lake, study was carried out for the period of two year from July 2013 to June 2015. Monthly water samples and aquatic insects were collected to analyse different physico-chemical parameters and diversity indices. The status of lake was investigated on the basis of obtained results of physico-chemical parameters of water and diversity indices of aquatic entomofauna.