BACKGROUND About 10% of infertilities with obstructive azoospermia are congenital and caused by CF gene mutations. M469I mutation was observed for the first time in Taiwanese patients. This mutation not only causes CF, but also may be the origin of infertility too. OBJECTIVE In this study, we aimed in designing a rapid, reliable RFLP-PCR procedure for detection of M469I mutation. The correlation and association between M469I mutation with infertility was investigated in this study. METHODS one hundred ten patients (90 non obstructive and 20 obstructive) and 60 normal individuals were considered in this study. M469I mutation was detected using RFLP-PCR. This technique was completely designed for M469I genotyping, for the first time in our study. Amplification of the region surrounding the mutation in exon 10 of CFTR gene was then performed. RFLP analysis was carried out using the NdeI restriction enzyme. RESULTS All genomic DNA samples were genotyped successfully. M469I mutation was observed only in patients group. Therefore, genotype containing mutant allele (GT) has been detected only in the patients group. There was no significant correlation between GT and TT genotypes with infertility (p=0.437). CONCLUSIONS The M469I mutation has only been observed in Exon 10 CFTR gene of infertile patients, not in the control group. This mutation causes congenital bilateral absence of vaz deferens and finally infertility. This indicates a strong association between the M469I mutation and male infertility. Therefore, this is a CF-causing CFTR mutation that could be considered as a cause of infertility.