Particle Image Velocimetry (PIV) is a method to measure space- and time-resolved flow velocities in fluids. I will work a lot with this method during my PhD. In the past, I got to know some commercial PIV software systems (e.g. "Flowmanager" and "VidPIV"), but I was never totally happy with these. I also had a look at several free PIV systems (mostly based on MATLAB), but these were not suitable for my demands. Since I am going to spend a lot of time with PIV calculations, E.J. Stamhuis and me recently developed a PIV software (called PIVlab) that takes advantage of numerous MATLAB features. I also created an extensive GUI for the software which makes it easy to get results with ease.