Analysis of 133 plankton, 462 otter trawl, and 124 shore seine samples from Lake Pontchartrain and adjacent waters of southeastern Louisiana suggests the following pattern for the life history of the blue crab in the area, although details are in need of confirmation. Mating takes place in the fresher areas followed by migration of the mated females to more saline waters. After hatching the young migrate in toward the estuaries where most of the growth takes place. The first wave of young seems to arrive in Lake Pontchartrain in May, and crabs spawned in the spring appear to reach a size of about 65 mm. by September of the first year. The relative absence of adults from winter collections suggests migration or hibernation. Food habits, parasites, and periodicity are discussed.