Forensim is a new package for the R statistical software that is dedicated to forensic DNA evidence interpretation. As far as we know, forensim is the first open-source tool that allows for the simulation of data encountered in forensic genetics studies. The package also implements common statistical methods used for reporting the weight of DNA evidence. Forensim is written in the R language and is freely available from http://forensim.r-forge.r-project.org. This paper presents an overview of the software's functionalities. (Published Abstract)