ObjectiveTo find the best feed and feed supplier for 24-month rodent carcinogenicity studies by assessing the quality, supply risks and price of three rodent feeds. MethodsSamples of the MF18 feed (Japan), LabDiet feed (USA) and SPF domestic rodent feed (Beijing) were sent to a professional laboratory for testing the conventional nutrients, metals and pesticides, and microbiological indicators, and to evaluate the quality of the feeds. Risks on feed transport and non-controllable factors which might affect feed quality and supply were evaluated. The price of each feed as a reference factor was also considered. ResultsThe quality of the three feeds met the requirements of standard GB14924-2001. According to the evaluation criteria for general toxicological indicators concerned in toxicity studies, the quality sort of the three feed was ranked as:MF18 feed (the best) -> LabDiet feed (better) -> local feed produced in Beijing (good). There were significant risks in transportation and supply for the imported feeds. The price of the domestic feed was relatively cheap but was not considered as a critical factor. ConclusionsAfter a comprehensive comparison, the special customized domestic feed is selected for the 24-month carcinogenicity study to be conducted in the National Centre for Safety Evaluation of Drugs.