RecMin is a software to identify ancestral recombination events from population genetic data.Under certain assumptions the pattern of diversity at a collection of linked sites provides information allowing us to detect historic recombination events. The program RecMin.c calculates a lower bound on the number of recombination events required to construct any history of a sample, under the assumption that each segregating site has mutated only once since the most recent common ancestor of the sample. Such a lower bound is appropriate, since many historical recombinations are typically undetectable. It gives a measure of what extent the sample history differs from a simple tree structure, and can show if there is regional clustering of the detectable recombinations.