Copyright © International Association for Food Protection. The behavior of radiocesium in wild animal meats upon cooking was investigated. The ratio of the concentration change (processing factor, Pf), remaining ratio (food processing retention factor, Fr), and removal ratio of radiocesium in the meats by grilling, boiling, and steaming were determined. Differences in cooking methods, rather than differences in meat parts or animal species, clearly influenced the Pf, Fr, and removal ratios. The mean Fr values were 0.9 (range, 0.7 to 1.0) for grilling, 0.6 (range, 0.4 to 0.7) for boiling, and 0.5 (range, 0.4 to 0.7) for steaming. The removal effect of grilling (11%) was lower than that of boiling (41%) or steaming (47%). The mean value of Pf was 1.2 (range, 1.1 to 1.6) for grilling, 0.8 (range, 0.6 to 0.9) for boiling, and 0.8 (range, 0.7 to 1.0) for steaming. The radiocesium concentration in the meats increased only upon grilling, but not by boiling or steaming. This difference is due to the lower removal effect of grilling than that of boiling and steaming. Therefore, boiling and steaming were more effective than grilling for removing radiocesium and reducing its concentration in wild animal meats. Furthermore, the ratio of water content fluctuations due to boiling was negatively correlated with Pf and Fr. It was evident that greater reductions in water content resulted in lower concentrations and improved radiocesium removal in the meats. These results suggest that some of the radiocesium naturally present in the meats is soluble in water and that the radiocesium dissolved in water can be removed from the meat with the release of water from the tissue.