The increasing use of animal models in the study of cataract has been one of the most important trends in lens research over the last two decades. The number of animal models available for both hereditary congenital cataracts and for maturity-onset cataracts has grown substantially during this time. Analysis of some of these systems by biochemical and molecular biology techniques has resulted in significant and often surprising insights into the basic biology of the lens, as well as the process of cataractogenesis. The following is a brief overview of those animal models for which biochemical studies have been reported.