FamLinkX provides an easy use graphical user interface (GUI) which allows for calculations accounting for linkage, linkage disequilibrium (LD) as well as mutations given some genetic data for a set of persons and some relationship hypotheses. The main function of FamLinkX is to calculate case specific likelihood ratios (LR) for two (or more) hypotheses with observed DNA-data for X-chromosomal DNA markers. In addition, it is possible to do simulations for two or more pedigrees (hypotheses) to study the impact of ignoring linkage and/or linkage disequilibrium for X-chromosomal STR markers. The software is developed by Daniel Kling at Norwegian Institute of Public Health, Norway, Andreas Tillmar at National Board of Forensic Medicine, Sweden, Thore Egeland at Norwegian University of Life Sciences and Petter Mostad at Chalmers University, Mathematical Sciences, Sweden.