Male infertility cases presenting with obstruction of the seminal tract may be primary or secondary to inflammatory events and/or surgery. The most common primary obstructive malformation of the seminal tract is bilateral agenesis of the vas deferens (CBAVD), a condition found frequently associating cystic fibrosis. Cystic fibrosis (CF) disease is caused by mutation in the cystic fibrois transmembrane conductance regulator (CFTR) gene. The most common mutation responsible for the expression of the typical (CF) symptoms including CBAVD is the F508 mutation. In Egypt, our retrospective study tried to define the frequency of F508 CFTR gene mutation in association with azoospermia in patients with CBAVD. Results showed that the frequency of F508 mutation of the CFTR gene in thirty patients presenting with congenital bilateral absence of the vas deferens was comparatively low (6.7%) compared to a higher frequency worldwide (66.6%). Anomalies of the seminal vesicles might be associated with the condition of CBAVD. Such anomalies can be detected by transrectal ultrasonography and fructose levels in semen.