【Abstract】 Objective To learn about the spontaneous non-neoplastic lesions and their incidences. Methods The control group of a combined chronic toxicity and carcinogenicity test include 60 male and 60 female Specific Pathogen-Free Wistar rats (4 weeks old ). The rats were acclimated for 1 week prior to initiation of the test. The rats were fed with conventional feed for 104 weeks and then sacrificed for histopathological examination. Results Various non-neoplastic lesions of the rats and their incidences were analyzed and reported. The lesions with high incidence in male rats occurred mainly in kidney, heart, liver and testis, and the lesions with high incidence in female rats occurred mainly in liver, adrenal gland and kidney. Conclusions The data about non-neoplastic lesions of Wistar rats reported in this paper can provide some reference for relevant technical staffs.