Preloading debug information based on the increment of application

A method, computer program product and system are provided for preloading debug information based on the presence of incremental source code files. Based on parsed input parameters to a source code debugger, a source code repository and a local storage area are searched for an incremental file. In response to the incremental file being located, a preload indicator in the incremental file, which is a source code file, is set. Based on the preload indicator being set, debug symbol data from the incremental file is merged to a preload symbol list. In response to receiving a command to examine the debug symbol data from the incremental file, the preload symbol list is searched for the requested debug symbol data.