CPSign is an Open Source Software tool for QSAR modeling using conformal and probabilistic prediction. Several descriptors can be computed, such as the Signatures molecular descriptor, ECFPs and physico-chemical using the CDK library, and it includes standard data preprocessing transformations for tasks such as feature scaling and data filtration. It comes with LIBLINEAR and LIBSVM for training underlying models, but it is possible to extend to use other algorithms. It is written for the Java Virtual Machin