Fatigue testing control and data acquisition system based on a 16 bit personal computer was developed. The system developed in this study allows one to perform multi-step programmed loading fatigue tests and pseudo-random loading fatigue tests, including conventional constant amplitude loading tests. In the data acquisition system, three parameters as load, total displacement and differential displacement can be measured simultaneously. For accurate monitoring of fatigue behavior, noise reduction software was also made. The data acquisition system developed in this work was successfully utilized for fatigue researches of welded steel specimens and composite materials.