We demonstrate fabrication of bottom gate/top source-drain contacts for p-channel (small molecule) organic field-effect transistor (OFET) using pentacene as an active semiconductor layer and silicon dioxide (SiO2) as gate dielectric. The device exhibits a typical output curve of a field-effect transistor (FET). Furthermore, analysis of electrical characterization was done to investigate the source-drain voltage (Vds) dependent mobility. The mobility which calculated using MATLAB simulation exhibited a range from 0.0234 to 0.0258 cm2/Vs with increasing source-drain voltage (average mobility was 0.0254 cm2/Vs). This work suggests that the mobility increase with increasing source-drain voltage similar to the gate voltage dependent mobility phenomenon.