Introduction. Azoospermia can be obstructive (OA) and non-obstructive (NOA). Given the increased incidence of maturation arrest histological phenotype, it is now becoming increasingly difficult to estimate azoospermia type before histological assessment. The micro-TESE techniques allow the identification of foci of spermatogenesis in non-obstructive forms and only the histological examination will provide an objective and definitive testicular phenotype. For greater accuracy, immunohistochemical techniques are needed in order to assess additional risks. Material and methods. 23 testicular biopsies were studied, obtained from 12 patients with azoospermia. Presumably 8 patients with ANO and 4 patients with AO (according to testicular volume, FSH, LH, genetic evaluation). All 23 preparations with tissue fixation in Bouin solution for at least 24 hours. Conventional histopathological evaluation was done for all stainings with immunohistochemistry for PLAP, MAGE4, INSL3 antigen in selected patients. Results. The histological results confirmed in 10 cases the diagnosis of NOA, 2 cases with the prediction of OA before intervention was not confirmed. The histological phenotype Sertoli cell-only syndrome, complete form, was found in 7 cases, the maturation arrest, also complete form, was found in 1 case and mixed atrophy in 2 cases. All preparations (18) were evaluated negatively for PLAP antigen. MAGE4 antigen was positively confirmed in 5 cases - 2 cases with OA, 2 cases with mixed atrophy and 1 with maturation arrest. MAGE4 was absolutely negative in biopsies of patients with Sertoli cell-only syndrome. INSL3 antigen was strongly fixed in tissues with OA and maturation arrest, significantly less fixation was observed in tissues with Sertoli cell-only syndrome and mixed atrophy. Conclusions. Hormones, ultrasound evaluation of the testicles, testis volume and available genetic tests have a predictive value in differentiating OA from NOA. The histological and immunohistochemical evaluation is accessible, establishes the testicular phenotype accurately and guides us in the patient’s management.