Crustacean abundance, distribution and taxonomic composition were determined in intake (Tabbs Bay and Cedar Bayou) and discharge (Trinity Bay) areas before operation (October 1969 through September 4, 1970), during operation of one 750 mw unit (September 5, 1970 through February 1, 1972), and during operation of two 750 mw units (February 2 , 1972 through December 1972) of the Cedar Bayou Electric Power Station, Chambers County, Texas. Otter trawls, bag seines and push nets were used in sampling. Initial plant operations were erratic. Mechanical problems forced plant shut-downs during May 24 through June 3 and July 7 through September 10, 1971. These were periods when thermal stress would have been higher had ambient bay temperatures been increased by addition of above-ambient thermal discharge. These occurrences and implementation of the 2600-acre cooling pond on April 27, 1972, resulted in little elevation in ambient temperatures during warmest periods. Grass shrimp (Palaemonetes pugio), brown shrimp (Penaeus aztecus), white shrimp (Penaeus setiferus), and blue crab (Callinectes sapidus) comprised 98.55% of the total crustacean catch.