Insulin-like growth factor binding protein 6 (IGFBP6) is a key factor in regulating the effects of insulin-like growth factor 2 (IGF2) on the animal growth and development, but the mechanism is far from known. In this study, the 5’-terminal sequence of the IGFBP6 gene (from −920 to −1 bp) which may regulate gene expression was sequenced in the Bama mini-pigs, the Tibetan mini-pigs, the Landrace pigs, the Large White pigs and the Northeast wild boars to screen for the single nucleotide polymorphisms (SNPs) and analyze the relations with the body size traits of swine through a chi-square test analysis. The genotype frequencies of the SNPs in the 5’-terminal sequence have shown that c.-726C > T, c.-722T > C, c.-535C > A, c.- 488T > C, c.-403A > G, and c.-378T > C may be related to the dwarf traits of the Bama mini-pig and the Tibetan minipigs (P < .05). A haplotype analysis of the 5’-terminal sequence of the IGFBP6 gene in the Landrace pigs, the Large White pigs and the Northeast wild boars found the two SNPs at −403 nt and −378 nt were in linkage and formed three kinds of haplotypes; AT was the dominant haplotype and the haplotype block was not formed in the Bama mini-pigs and Tibetan mini-pigs. Above all, the SNPs and haplotypes of the 5’-terminal sequence of the IGFBP6 gene may be involved in the regulation of swine body size.