It was observed that the spermatogenic cells apoptosis dramatically increased in infertile man. Cloning of novel spermatogenic cell-specific gene related to apoptosis is of momentous physiological and pathological significance to illustrate the apoptosis mechanism and the biology process of spermatogenic cells. A novel mouse gene full-length cDNA sequence-SRG2 was identified (GenBank accession number AF395083), which was significantly changed in cryptorchidism, from a mouse testis cDNA library using a cDNA fragment (GenBank accession number BE644542) as an electronic probe. SRG2 was 1,088 bp in length. The putative protein encoded by this gene was 295 amino acids with a theoretical molecular weight of 33,579 kDa and isoelectric point of 9.64. The sequence shared no significant homology with any known protein in databases except TSARG2, with which its homology was 78%. RT-PCR showed that SRG2 was expressed significantly in testis. Using molecular beacon probe to examine the mRNA expression level of SRG2 gene in cryptorchid testis of various stages, we found that the gene was up-regulated distinctly. Therefore, we conclude that this gene plays an important role in cryptorchid testis.