The phosphodiesterase 4B (PDE4B) gene is located at 1p31, a susceptibility region for schizophrenia (SZ). Moreover, PDE4B interacts with DISC1, which is a known genetic risk factor for SZ. Recently, it was reported that the PDE4B gene is associated with SZ in Caucasian and African American populations. In this study, case-controlled association analyses were performed in the Japanese population to determine if the PDE4B gene is implicated in SZ. Thirteen single nucleotide polymorphisms (SNPs) were analyzed in 444 schizophrenic patients and 452 control subjects. Three SNPs (rs2180335, rs910694 and rs472952) were significantly associated with SZ after applying multiple test correction (p=0.039, 0.004 and 0.028). In addition, a significant association was found between specific haplotypes (rs2180335 and rs910694) and SZ (permutation p=0.001). Our result suggests that variations at the PDE4B locus may play a significant role in the etiology of SZ in the Japanese population.