Although we failed to show that genetic markers in GABRB2 (S1, S3, S5, S29, S31, and S32) were associated with heroin dependence in allele and genotype levels (P > 0.05), very significant associations were detected at haplotype level, especially in haplotypes only containing SNPs in the S1-S29 segment (S1, S3, S5, and S29) (PCorr < 0.001; PGlobal = 0.0001) (Table 1). Here, GABRB2 is linked to heroin dependence.