The proportional-integral-derivative (PID) controller design for time-delay systems is a classical problem. We consider a general case where the three controller gains (k P , k I , and k D ) and the delay (τ) are all treated as free parameters. Our objective is to characterize the stability set in the parameter space of (k P ; k I ; k D ; τ). The problem is very involved due to the theoretical difficulties. In this paper, we introduce a MATLAB-based toolbox, called PID-Design-Delay toolbox. It is developed based on some recently-reported theoretical results, by which the problem can be systematically solved. The user is only required to input the necessary information via the graphical user interface (GUI) and then the stability analysis may be automatically fulfilled by the toolbox.