The effect of source of dietary fat on the capacity of pig adipose tissue to synthesize fat was investigated. In addition, the influence of source of dietary fat on the activities of malic enzyme, citrate cleavage enzyme, performance and carcass characteristics were also determined. The addition of 10% dietary fat, as corn oil, lard, tallow or coconut oil, resulted in a marked depression in the conversion of glucose-U-14C into fatty acids. The activities of malic enzyme and citrate cleavage enzyme were also depressed in adipose tissue homogenates of pigs fed diets containing 10% dietary fat, regardless of source. Results of the studies reported suggest that a high linoleate content of the dietary fat is not a prerequisite for the inhibition of fatty acid synthesis in pig adipose tissue. Therefore, it appears that the pig is similar to the rat in that all dietary fats, saturated and unsaturated, are equally effective in inhibiting fatty acid synthesis.