Abstract: Disclosed herein is a system for facilitating Change Impact Analysis (CIA) using modular program dependency graphs. Further, the system may include a communication device configured for receiving a source code for a software application and one or more changed lines corresponding to the source code from a user device, and transmitting one or more impacted lines from the source code associated with the software application to the user device. Further, the system may include a processing device configured for analyzing the source code to determine one or more modules, generating one or more modular Program Dependency Graphs (mPDGs) based on the analysis, updating at least one mPDG based on the one or more changed lines to obtain the at least one updated mPDG, searching the mPDG based on search expressions associated with the one or more changed lines, and calculating one or more impacted lines based on the searching.