Mg-doped InxGa1-xN alloys were grown by metal organic chemical vapor deposition (MOCVD) on semi-insulating c-GaN/sapphire templates. Hall effect measurements showed that Mg-doped InxGa1-xN epilayers are p-type for x up to 0.35. Mg-acceptor levels (EA) as a function of x, (x up to 0.35), were experimentally evaluated from the temperature dependent hole concentration. The observed EA in Mg-doped In0.35Ga0.65N alloys was about 43 meV, which is roughly 4 times smaller than that of Mg doped GaN. A room temperature resistivity as low as 0.4 Ωcm (with a hole concentration ∼5 1018 cm -3 and hole mobility ∼3 cm2/Vs) was obtained in Mg-doped In0.22Ga0.78N. It was observed that the photoluminescence (PL) intensity associated with the Mg related emission line decreases exponentially with x. The Mg energy levels in InGaN alloys obtained from PL measurements are consistent with those obtained from Hall-effect measurements.