The reproductive performance of female cats is severely affected by dietary taurine deficiency resulting in excessive reproductive wastage, including frequently resorbed or aborted fetuses and stillborn or low birth-weight live kittens. These studies were performed using female cats fed a completely defined purified diet (taurine-free) alone or supplemented with taurine for greater than or equal to 6 mo before mating, and their breeding performance was monitored for several years. Diets containing 0, 0.005 or 0.01% taurine produced severe taurine depletion and poor reproductive performance. Those containing 0.05, 0.2 or 1% taurine resulted in no apparent abnormalities and a normal breeding performance. A diet containing 0.02% taurine resulted in no apparent abnormalities and a normal breeding performance. A diet containing 0.02% taurine resulted in modest taurine depletion and a partially compromised reproductive performance. Kittens from taurine-deficient mothers have a poor survival rate and grow at a slower rate than kittens from females fed an adequate taurine diet. The brain weights of kittens from taurine-deficient mothers are significantly smaller than normal, both at birth and at weaning at 8 wk. Surviving kittens exhibit a number of abnormalities. The differences in maternal dietary taurine are reflected in the taurine concentrations found in the milk of lactating females. Our results strongly suggest that a certain amount of taurine is mandatory for survival and normal development in the cat.