RMBlast is a RepeatMasker compatible version of the standard NCBI BLAST suite. The primary difference between this distribution and the NCBI distribution is the addition of a new program "rmblastn" for use with RepeatMasker and RepeatModeler. RMBlast supports RepeatMasker searches by adding a few necessary features to the stock NCBI blastn program. These include: - Support for custom matrices ( without KA-Statistics ) - Support for cross_match-like complexity adjusted scoring (Cross_match is Phil Green's seeded smith-waterman search algorithm: www.phrap.org ) - Support for cross_match-like masklevel filtering.