This is a case report of a thirty-year-old-man consulting for a primary infertility that was diagnosed four years ago. Andrologic exam was normal. Two spermograms found normal spermatic parameters. An uro-genital echography with a RMI showed that a unilateral agenesia of the left vas deferens in the pelvic portion. Then, a composite heterozygoty of the CFTR gene (DeltaF508/V938G) was found. This is the first time that the association of these two mutations has been described. This case also makes it possible to wonder about the need for realizing, or not, a systematic basis imagery (ultrasound examination in first), in the event of infertility of the couple. In this context, the discovery of an echographic anomaly made it possible to identify CFTR mutations, whose physiopathological implication in the infertility can be discussed (CFTR related disorders)...