Tssk2, a member of the testis-specific serine/threonine kinase (TSSK) family, is expressed predominantly in the testis and is crucial for the formation and function of sperm cells in the mouse. Targeted deletion of Tssk1 and Tssk2 in male chimeric mice caused infertility because of haploinsufficiency of the genes. Therefore, it is reasonable to postulate that mutations in the human homolog TSSK2 gene may also play a role in impaired spermatogenesis in humans. To explore the possible association between mutations in the TSSK2 gene and idiopathic infertility in humans, mutation screening of the gene in 494 patients with azoospermia or severe oligozoospermia and 357 fertile controls was performed using denaturing high-performance liquid chromatography and DNA sequencing. As a result, 4 single-nucleotide transitions were identified, including c.80A>G (rs3747052), c.774C>T (rs1052756), c.839C>T (rs1052763), and c.1026G>A (rs1052773). Among them, significant differences in polymorphism frequencies were observed of c.80A>G (rs3747052) and c.774C>T (rs1052756) between the patients and controls; the allele G of c.80A>G (rs3747052) and allele T of c.774C>T (rs1052756) seem to be risk factors for the development of spermatogenic impairment, suggesting that the TSSK2 gene may be associated with male idiopathic infertility in humans.