We present electrical resistivity measurements on U 1-xLa xPt (x=0, 0.1, 0.2, 0.5, 0.8, 0.9, 1) between 2 and 1000 K. The compounds exhibiting ferromagnetic behaviour (xles0.3) display a maximum at low temperatures and some of them a minimum at higher temperatures. For the non-ordered compounds (xges0.5) the resistivity increases continuously with temperature. A common feature of the U-rich compounds is the existence of a negative logarithmic temperature dependence of the total resistivity above the maximum, whereas a combination of a linear term plus a logarithmic term is found for the others. Under a Kondo-like framework, a breakdown of the Mattiessen rule is suggested.