Human brain cDNA labrary was screened with probes (Cam 1 and Cam 2, Cam 1 and Cam 5) constructed from the common region of rat and bovine opioid-binding cell adhesion molecule (OBCAM) cDNA. A polymerase chain reaction product of 528 bp was obtained from a human brain cDNA library. We found that plaques contained probe sequence. Only one clone was isolated and sequenced. It has a 75.0% homology to known OBCAM bovine and 76.3 % to known human cDNA. This study suggests that it may be a family of OBCAM-Iike genes.