Aim: The current voltage characteristics of Silicon based BIOFET and Germanium based BIOFET are simulated by varying their oxide thickness ranging from 1nm to 100nm. Materials and Methods: The electrical conductance of Silicon based BIOFET (n=320) was compared with Germanium based BIOFET (n=320) by varying oxide thickness ranging from 1nm to 100nm in the NanoHub© tool simulation environment. Results: Germanium based BIOFET has significantly higher conductance than Silicon based BIOFET. The optimal gate oxide thickness for maximum conductivity was 1nm for Silicon based BIOFET and 35nm for Germanium based BIOFET. Conclusion: Within the limits of the study, Germanium based BIOFET with oxide thickness of 35nm offers the best conductivity.