Effects of crowding were investigated with respect to growth, feeding, food conversion, mortality, and health of bullfrogs (Rana catesbeiana) up to 9 months of age. No statistically significant differences were found with regard to growth, food consumption, food conversion, mortality, or health. The average food conversion (C) was less than 2.6 during the first two months of growth and values between 1.65 and 1.99 were obtained. By the third month most values approached 3.00. A high correlation was found between gain and food conversion. Daily consumption as high as 350/0 was recorded. The fastest growing bullfrogs approached or exceeded 226 g (lh lb.) in 8 months from metamorphosis. Analysis of 68 frogs for sexual maturity showed that males had motile sperm by 4 months of age and a weight of 32 g. Analysis of females indicated eggs approaching maturity may be produced as early as 6 months from metamorphosis. Under natural conditions, crayfish make up a large portion of the bullfrog diet. Given a choice they prefer tadpoles, fish and crayfish in that order.