OBJECTIVE Men with nonobstructive azoospermia (NOA), cryptozoospermia and severe oligozoospermia are candidates for microdissection testicular sperm extraction (micro-TESE) and intracytoplasmic sperm injection (ICSI). We sought to evaluate micro-TESE outcomes and the need for bilateral testicular exploration in the three groups of men. METHODS We conducted a retrospective study of 233 consecutive micro-TESEs in men with nonobstructive azoospermia (n = 173), cryptozoospermia (n = 43) and severe oligozoospermia (n = 17). The decision to terminate the micro-TESE after a unilateral or bilateral testicular exploration was determined at the time of surgery and was based on the presence or absence of mature spermatozoa in the harvested micro-biopsies. Final assessment of sperm recovery, on the day of ICSI, was reported as successful (available spermatozoon for ICSI) or unsuccessful (no spermatozoon for ICSI). RESULTS Unilateral testicular exploration resulted in successful sperm retrieval in 43% (75/173), 79% (34/43) and 100% (17/17) of men with NOA, cryptozoospermia and severe oligozoospermia respectively. Therefore, 57%, 21% and none of the men with NOA, cryptozoospermia and severe oligozoospermia, respectively, required a bilateral micro-TESE. Overall, micro-TESE resulted in successful sperm retrieval in 52% (90/173), 91% (39/43) and 100% (17/17) of men with NOA, cryptozoospermia and severe oligozoospermia respectively. CONCLUSIONS Our data indicate that men with severe oligozoospermia are unlikely to require a bilateral testicular exploration at micro-TESE. Moreover, most cryptozoospermic men will have a successful sperm retrieval by micro-TESE with the majority of these patients requiring a unilateral exploration. In contrast, over 50% of the men with nonobstructive azoospermia will require a bilateral micro-TESE.