Identification of genes specifically expressed in adult and fetal testis is important in furthering our understanding of testis development and function. In this study, a novel human transcript, designated human testis cAMP-responsive element-binding protein (htCREB), was identified by hybridization of adult and fetal human testis cDNA probes with a human cDNA microarray containing 9216 clones. The htCREB transcript (GenBank Accession no. AY347527) was expressed at 2.35-fold higher levels in adult human testes than in fetal testes. Sequence and ntBLAST analyses against the human genome database indicated that htCREB was a novel splice variant of human CREB. RT-PCR-based tissue distribution experiments demonstrated that the htCREB transcript was highly expressed in adult human testis and in healthy sperm, but not in testes from patients with Sertoli cell-only syndrome. Taken together, these results suggest that the htCREB transcript is chiefly expressed in germ cells and is most likely involved in spermatogenesis.