Current Texas law allows the culture of exotic and native penaeid shrimp in private waters under provisions of a Texas shellfish culture license. Because of superior growth and survival characteristics exhibited under pond culture conditions, the Pacific white shrimp (Penaeus vannamei) has emerged as the primary penaeid shrimp commercially cultured in Texas. Recently, shrimp believed to be Pacific white shrimp were collected by commercial shrimpers in the Brownsville, Texas, ship channel. These specimens were morphologically and biochemically compared to native northern white shrimp (P. setiferus) and to Pacific white shrimp from 2 sources: the Parita Gulf, near Panama City, Panama, and commercial rearing ponds, Palacios, Texas. Comparison of morphometric and meristic characteristics and soluble protein profiles isolated by isoelectric focusing confirmed the identification ofthese shrimp as Pacific white shrimp. Because these are exotics, investigations into potential ecological and economic impacts of the introduction into Gulf of Mexico waters are needed.