Verification before fabrication is one of the main objectives of computer aided design. The highly complex designs implemented in VLSI, ULSI and WSI technologies need more sophisticated tools for verifications on the same level of complexity. Simulation as a process of modeling a real system on computer is an imperative tool especially in the earlier phases of design, where a lot of modifications can be done on the design to get a free error design. The latest development in the capabilities of personal computers makes it possible to develop many applications on PC platforms. In this paper we propose an incremental behavioral simulator for digital systems to run on PC platforms. The simulator is used to evaluate the performance of digital circuits without hardware realization of such systems. The simulator implements the event-driven mode of operation. The incremental facility of the simulator reduces the overall simulation time where the part affected by a change is only resimulated. Different case studies have been evaluated on the proposed simulator. Results of simulation time as a function of circuit size are presented.