The purpose of this study is to introduce "IRTPRO 2.1 for Windows" computer software which enables to perform analysis based on different item response theory (IRT) models. In this context, the study is focused on the necessary hardware features for IRTPRO 2.1 software, access to the program, running the program, analysis, output files, the goodness of fit index and descriptive statistics. In addition, sample applications are made with simulative data belonging different structures including 20 items and 2000 examinees. Based on the obtained results it is intended to provide information about the amount of time needed to analyze different IRT models. As a result of compilations and experiences of researchers, a prior knowledge have tried to give about IRTPRO 2.1, the advantages and disadvantages of the program were discussed. IRTPRO 2.1 is a practical software and allows to execute functions, which can be performed by several softwares for data analysis based on IRT, with one program. Researchers who wish to make use this program in their research are recommended to investigate the trial version of the software in terms of strengths and limitations and then decide whether to buy a license.