['To identify whether epistasis between TG and HSD17B4 and whether polymorphisms in HSD17B4 are associated with premature ovarian failure (POF).', 'Case-control genetic association study.', 'Research laboratory of a university.', 'Female patients with POF (98) and controls (218) of Korean ethnicity participated in this study.', 'None.', 'Genotype distribution, haplotype (HT) inference, and gene-gene interaction.', 'Distribution of one haplotype (A-G-A-A-G-G) on the HSD17B4 gene was significantly different between the POF group and the control group in a dominant model. In addition, the combined effect of the single nucleotide polymorphisms (SNPs) HSD17B4 rs28943592 and TG rs2076740 was significantly associated with POF (odds ratio = 7.74, 95% confidence interval = 1.67-35.94), although a significant association was not observed in the single SNP model.'] Is epistasis between the HSD17B4 and TG polymorphisms associated with premature ovarian failure?