Open Access Software for Cardiotocography Analysis (CTG-OAS) is developed to analyze fetal heart rate (FHR) signals. The software provides several tools to characterize the FHR signals. The features obtained from different origins, such as morphological, linear, nonlinear, time-frequency and image-based time-frequency domains are used as the inputs to classifiers. In other words, the significant analysis steps regarding the machine learning are taken into account by the software. CTG-OAS is developed for academic purposes and it will be distributed free of charge.