Leptospirosis, an emerging infectious disease caused by pathogenic Leptospira, is a worldwide zoonosis of human and veterinary concern. Transmission to humans occurs through contact with wild or domestic animal or exposure to contaminated soil or water. In the urban setting, L. interrogans serovar Copenhageni colonizes most of the brown rat (Rattus norvegicus) population and is the predominant serovar causing disease in humans. Leptospiral LPS can elicit protective immunity but is serovar specific (Faine et al., 2nd edition, Australia:MediSci, 1999). Due to the extensive serological diversity of leptospires (~250 serovars) a search for conserved surface-exposed proteins that may stimulate heterologous immunity is being followed. That`s possible through the use of the bioinformatics tools and the whole-genome sequences of L. interrogans serovar Copenhageni (Nascimento et al., J. Bacteriol. 186 (7), 2164-72, 2004). The chosen genes encode for two probable lipoproteins, LIC10368 and LIC10494, predicted to be exported to membrane and lipidated. The genes were amplified by PCR methodology and cloned into pDEST17^TM, an E. coli vector. The recombinant proteins were expressed in fusion with six histidine residues (6xHis-tag) at N-terminus that allow protein purification by metal-affinity chromatography. After purification by nickel-charged Sepharose beads, the recombinant proteins were analyzed by circular dichroism (CD) spectroscopy that revealed well folded proteins, with characteristic spectra of alpha-helix structures. Ten female BALB/c mice were immunized subcutaneously with 10mg of purified recombinant proteins and boostered after 14 days. The mice were bled from the retro-orbital plexus, and the pooled sera were analyzed by enzyme-linked immunosorbent assay (ELISA). Recombinant proteins were also evaluated by western blotting using serum from mice immunized with bacteria cell extracts. Both recombinant proteins showed reactivity especially with sera from mice immunized with membrane preparation (Triton X-114^TM fraction). These results corroborate with their predicted cellular localization in the bacterial membrane, possible outer membrane, by PSORT program. These recombinants will be further analyzed by western blotting using serum from human patients diagnosed with leptospirosis. These tests should allow preliminary identification of proteins that might be useful for diagnosis of the disease as well as potential vaccine candidates.