The Pulicat Lake is the second largest brackish-water ecosystem in India and it has a high water spread of 460 sq. km and low water spread area of 250 sq. km. This lagoon is drained by three larger inflows and many minor inflows and important habitat for different fish species. The aim of the study is to identify the distribution and diversity finfishes in Pulicat Lake. Fishes were collected from five different landing centres such as Pazhaverkadu, Annamalaicheri, Arambakkam, Sulurpet and Irukkam. During our study period (August 2012 - March 2013), a total number of 44 finfish species belonging to 10 orders, 33 families was recorded. Among them, Siganidae and Cichlidae family was highest followed by Tetraontidae, Theraponidae, and Engraulidae. A Mugil cephalus (Mullet) are major contributory species for both spatial and temporal scale. High water spread and rainfall was found as significant factor for finfish species distribution.