Although provisional maximum tolerable daily intake and recommended guidelines have been established for fumonisins (FB) in food, few data are available concerning levels of FB inedible animal tissues. Such data are of particular interest in avian species that can tolerate relativelyhigh levels of fumonisins in their feed. Also, even if multiple contamination of animal feed bytoxins produced by Fusarium is very frequent, little is known about the consequences of multiplecontamination for FB levels in tissues. The aim of this study was to analyze the concentrationsof FB in the muscle and liver of chickens and turkeys fed with FB alone and with FB combinedwith deoxynivalenol (DON), and with zearalenone (ZEN). Experimental diets were formulated byincorporating ground cultured toxigenic Fusarium strains in corn-soybean based feeds. Control dietswere free of mycotoxins, FB diets contained 20 mg FB1+FB2/kg, and FBDONZEN diets contained20, 5, and 0.5 mg/kg of FB1+FB2, DON, and ZEN, respectively. Animals were reared in individualcages with free access to water and feed. The feed was distributed to male Ross chickens from the1st to the 35th day of age and to male Grade Maker turkeys from the 55th to the 70th day of age.On the last day of the study, the birds were starved for eight hours, killed, and autopsied for tissuessampling. No sign of toxicity was observed. A UHPLC-MS/MS method with isotopic dilution andimmunoaffinity clean-up of samples has been developed for analysis of FB in muscle (n = 8 per diet)and liver (n = 8 per diet). Only traces of FB that were below the LOQ of 0.25 µg/kg were found inmost of the samples of animals fed with the control diets. Mean concentrations of FB1, FB2, and FB3in muscle were 17.5, 3.39, and 1.26 µg/kg, respectively, in chickens, and 5.77, 1.52, and 0.54 µg/kg inturkeys, respectively. In the liver, the respective FB1, FB2, and FB3 concentrations were 44.7, 2.61, and0.79 µg/kg in chickens, and 41.47, 4.23, and 1.41 µg/kg, in turkeys. Cumulated level of FB1+FB2+FB3in the highly contaminated samples were above 60 and 100 µg/kg in muscle and liver, respectively.The concentrations of FB in the tissues of animals fed the FBDONZEN diet did not greatly differ fromthe concentrations measured in animals fed the diet containing only FB.