Non-obstructive azoospermia (NOA) is a condition of testicular failure caused by various factors. To retrieve sperm in NOA patients, microdissection testicular sperm extraction (micro-TESE) is a highly effective technique. The present study aimed to evaluate successful sperm retrieval (SSR) in NOA patients across different etiologies in the Iranian population to identify predictive factors. This retrospective analysis included 566 NOA patients undergoing micro-TESE from 2018 to 2023, with 58 histories of Cryptorchidism, 40 Klinefelter syndrome (KS), 6 Y chromosomal microdeletions (YCMDs), 6 histories of chemotherapy, 5 mumps orchitis, and 451 patients with idiopathic reasons. The overall SSR was 43.2%, with a significantly lower SSR in the KS group ( = .012). Patients with higher average ages tended to have higher SSR rates, especially in the idiopathic group. Hormone levels differed among the groups, with higher follicle-stimulating hormone and luteinizing hormone levels in the YCMDs group, higher testosterone levels in the idiopathic and Cryptorchidism groups, and higher prolactin levels in the KS group. There were no significant differences in other clinical characteristics between the SSR and sperm retrieval failure groups, except for a positive relationship between prolactin levels and SSR rates in the KS group ( = .45,  = .003). Our data underscores that underlying etiology and genetic background may reveal more valuable predictive value than age, hormone levels, and testicular volume. This finding suggests that no patient with NOA should be deprived of micro-TESE based on candidate predictors of SSR presented to date.