The diaminobenzidine method for catalase showed two distinct morphological populations of renal microbodies in healthy mature cats of both sexes. Microbodies in the proximal convoluted tubules, which in this species also contain abdundant neutral lipids, were polyhedral and had distinct marginal plates. Those in the remaining renal tubules, which are lipid-free, were rounder and less uniform in size. Both forms of microbodies had homogenous granular matrices without nuceloides. The morphological variations of the microbodies may depend on their association with renal lipids. The cat may serve as a model to explore functional or pathological relationships between microbodies and fat metabolism.