Summary: SCARF is a next-generation sequence assembly tool for evolutionary genomics that is designed especially for assembling 454 EST sequences against high quality reference sequences from related species. The program was created to knit together low coverage 454 contigs that do not assemble during traditional de novo assembly, using a reference sequence library to orient the 454 sequences. Availability: SCARF is freely available at http://msbarker.com/software.htm, and is released under the open source GPLv3 license (http://www.opensource.org/licenses/gpl-3.0.html). Contact: msbarker@indiana.edu 10.1093/bioinformatics/btp011