This volume contains the accepted full papers and extended abstracts of the 5th Brazilian Symposium on Bioinformatics held in Bu ´zios, Rio de Janeiro, Brazil from August 31 to September 3, 2010. The ?rstthree meetings ofthis series,which took place2002,2003,and 2004, were called WOB (Workshop on Bioinformatics). In 2005, the conference got its current name BSB and has since published its proceedings as a special issue of the series Lecture Notes in Bioinformatics (volumes 3594/2005, 4643/2007, 5167/2008, and 5676/2009). Its topics of interest vary in many areas of bioinformatics, including - quence analysis, motifs, and pattern matching; biomedical text mining; biolo- cal databases, data management, integration;biologicaldata mining; structural, comparative, and functional genomics; protein structure, modeling, and si- lation; gene identi?cation and regulation; gene expression analysis; gene and protein interaction and networks; molecular docking; molecular evolution and phylogenetics;computationalsystemsbiology;computationalproteomics;stat- tical analysis of molecular sequences; algorithms for problems in computational biology; as well as applications in molecular biology, biochemistry, genetics, and associated subjects. WewouldliketothankallrefereesandProgramCommitteemembersfortheir carefulworkinpreparingthis proceedingsvolume.Also,wewanttoacknowlegde the local organizers and their sta? for making this meeting possible. September 2010 Carlos E. Ferreira Satoru Miyano Peter F. Stadler Organization BSB 2010 was promoted by the Brazilian Computing Society (SBC) and was organizedbytheInformaticsDepartmentofthePontif´ ?ciaUniversidadeCat´ olica do Rio de Janeiro (PUC-Rio).