In this study we aimed to evaluate 21 candidate loci for bipolar affective disorder (BPAD) identified earlier in a large genome-wide association study. We evaluated 74 pedigrees with BPAD, with a total of 411 individuals, including 96 patients who fulfilled clinical criteria for BPAD according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition classification. Family-based association analysis was performed using the UNPHASED software. We identified a single nucleotide polymorphism (rs9834970) localized on chromosome 3p22.3, showing statistically significant association with BPAD after the Bonferroni correction for multiple comparisons (P(corrected)=0.0025) with an odds ratio=2.64 (95% confidence interval: 1.30-5.35). Single nucleotide polymorphism rs9834970 is located in an intergenic region and is not known to be associated to regulatory genomic sequences.