Congenital bilateral absence of the vas deferens (CBAVD) accounts for 2-6 percent of male infertility and up to 25 percent of incidences of obstructive azoospermia (OA). Men having azoospermia, teratozoospermia, and oligo asthenospermia had nonobstructive azoospermia (NOA). The relationship between cystic fibrosis transmembrane conductance regulator (CFTR) mutations and poor sperm quality remains to be controversial. In this review, the structure and function of CFTR gene mutations, their classes, their role in spermatogenesis, growth of vas deference, and their relation with CBAVD as well as with non-obstructive azoospermia will be included. Also, techniques for assisted reproductive technology (ART) will be simplified. Finally, the frequency of CFTR mutations in infertile males. Among them, German, Iranian, Chinese, Saudi Arabia, and Egyptian studies will be included. A discussion of their results will be done. The correlations of the results of these studies with the Egyptian ones will be summarized. Therefore, after intracytoplasmic sperm injection (ICSI) therapy, one can expect a higher frequency of CFTR mutations. The latter may increase the prevalence of cystic fibrosis (CF) in the patient's offspring. All patients with CBAVD should urgently undergo CFTR mutations screening, especially during pre-ICSI genetic counseling.