Objectives : Isolated cleft lip with or without cleft palate(CL/P) is among the most common human birth defects, with a prevalence of approximately 1 in 700 live births. The B-Cell Leukemia/lymphoma 3(BCL3) gene has been suggested as a candidate gene for CL/P based on association and linkage studies in some populations. This study tests for an association between markers in BCL3 and isolated, non-syndromic CL/P using a case-parent trio design, while considering parent-of-origin effects. Methods : Forty case-parent trios were genotyped for two single nucleotide polymorphisms(SNPs) in the BCL3 gene. We performed a transmission disequilibrium test(TDT) on individual SNPs, and the FAMHAP package was used to estimate haplotype frequencies and to test for excess transmission of multi-SNP haplotypes. Results : The odds ratio for transmission of the minor allele, OR(transmission), was significant for SNP rs8100239(OR=3.50, p=0.004) and rs2965169(OR=2.08, p=0.027) when parent-of-origin was not considered. Parentspecific TDT revealed that SNP rs8100239 showed excess maternal transmission. Analysis of haplotypes of rs2965169 and rs8100239 also suggested excess maternal transmission. Conclusions : BCL3 appears to influence risk of CL/P through a parent-of-origin effect with excess maternal transmission.