Onchocerciasis, also known as river blindness, is the second leading infectious cause of blindness worldwide. In order to successfully control this disease, the development of efficient diagnostic tools as well as effective treatments is imperative. A number of proteins have been proposed as vaccine and diagnostic candidates, yet none have been successfully advanced to the point of general clinical use. We have prepared major sperm protein 2 (MSP2) from Onchocerca volvulus as a possible diagnostic antigen for onchocerciasis. Importantly, recombinant MSP2 is dimeric in solution, identical to alpha-MSP from the roundworm, Ascaris suum. A panel of sera obtained from Cameroonian individuals afflicted with onchocerciasis positively responded to the recombinant MSP2. Our data suggest that MSP2, like the previously described antigen Ov16, can be utilized as a diagnostic onchocerciasis antigen for monitoring the interruption of transmission.