CDbg is a debugger for executables that are produced by Microsoft C/C++ compiler. This debugger focuses on speed, flexibility, and providing to programmer as much useful information as it is possible. Currently CDbg is capable of doing source code stepping, setting breakpoints, viewing callstack, and evaluating simple expressions. After making sure that listed things work robust, I will proceed to tackle down other features like user-written extensions and support for GCC and Clang.