EN
We present the results of measurements of electrical resistivity (ρ(T)) and magnetoresistance (Δϱ/ϱ_{0}(T)) on the solid solutions U_{1-x}Th_{x}Pt (x=0-0.8). The Curie temperature (T_{c}=21 K) found for the parent compound UPt, is steadily reduced upon the Th-substitution. The ρ(T) and Δϱ/ϱ_{0}(T) functions provide evidence of electron scattering due to spin fluctuations. The most interesting feature of Δϱ/ϱ_{0} is its high value of about -22% found for UPt and U_{0.9}Th_{0.1}Pt at their T_{c} and B=8 T. For samples with x ≥ 0.2, the value of Δϱ/ϱ_{0} at 4 K and 8 T increases with x and becomes positive for Th-composition x >= 0.6.