Silicon germanium (Si1−xGex) alloys have been grown by the floating zone method withxvarying from 0.5 to 20 wt %. Resistivity and Hall effect measurements have been carried out in the temperature range 80–410 K. The Hall mobility has been found to decrease with Ge concentration varying between 0.5 and 4.5 wt % and thereafter an increase has been observed. The Hall mobility has also been found to decrease with an increase in temperature in these alloys following theAT−yrelation, whereAis a constant andTis the temperature in K.