G eneralized peroxisome-deficient disorders including cerebro-hepato-renal Zellweger syndrome, neonatal adrenoleukodystrophy, and infantile Refsum disease are autosomal recessive diseases, where catalase-containing particles (peroxisomes) are morphologically absent. We previously isolated two Chinese hamster ovary (CHO) cell mutants (Z24 and Z65) that resemble the fibroblasts from patients with such diseases, in their defective peroxisome assembly (Tsukamoto, T., S. Yokota, and Y. Fujiki. 1990. J. Cell Biol. 110:651-660). Here we report isolation by the P9OH/UV method of a peroxisome-deficient CHO mutant, ZP92, of the third complementation group distinct from those of Z24 and Z65. Peroxisomal membrane ghosts were noted by immunochemical staining in all of the CHO mutants. Complementation analysis by cell fusion of the CHO mutants with cultured fibroblasts from patients with generalized peroxisomal disorders revealed that two CHO mutants (Z24 and ZP92) represent the human complementation groups, E (the same as group 1 in the U.S.) and C (the same as group 4), respectively. These CHO cell mutants are an apparently relevant animal cell model for studies on the molecular bases and primary defects of human peroxisome-deficient diseases.