SummaryIn order to assess the suitability of DNA flow cytometry of fine‐needle aspirates for quantiftring spermatogenesis, the results from DNA flow cytometry were compared to histological evaluation of testicular biopsies taken concomitantly from 171 previously maldescended testes. In 137 of 171 cases, sufficient material for flow cytometric as well as histological evaluation was obtained.Histological analysis of surgical biopsy specimens revealed spermatogenesis including the spermatid stage in 117 of the 137 gonads. In six of the 117 gonads no haploid cells were found using flow cytometry. On the other hand, surgical biopsies failed to reveal spermatogenesis in five cases in which the corresponding aspirates contained haploid cells. Both methods therefore seem equally sensitive in detection of spermatogenesis.Other types of histological patterns also corresponded to distinct DNA histograms.Thus, in 11 of 12 cases with Sertoli‐cell‐only pattern in all tubules, at least 95% of the cells had a diploid DNA content. Furthermore, predominance of tubules with maturation arrest at the primary spermatocyte level corresponded to an increased proportion of tetraploid cells.When compared to surgical biopsy, DNA flow cytometry of testiclar fine‐needle aspirates is a more objective, easy and rapid method, which is more convenient for the patient. This study has indicatedthat DNA flow cytometry is a suitable method of quantitative assessment of spermatogenesis. One of the first target groups might be men with azoospermia. In such men, DNA flow cytometric analysis of fine‐needle aspirates and surgical biopsy are apparently of equal sensitivity in detecting gonads with spermatogenesis. We conclude that DNA flow cytometry may become an alternative method for the quantification of sperma