In this article, we report the first study of the temperature dependence of the upper critical field on Ba1-x(subíndex) Kx(subíndex) BiO3(subíndex) . We measured the resistive transition on Ba1-x(subíndex) Kx(subíndex) BiO3(subíndex) single crystal down to 2 K in a pulsed magnetic field up to 35 T.