Infection and inflammation of the male reproductive tract are thought to be a primary aetiological factor of male infertility. Furthermore, several studies suggest that T lymphocytes are critically involved as regulator in the pathogenesis of male infertility under these conditions and are thought to induce autoimmune orchitis. In this context of autoimmunity the recently described T helper (Th) 17 subset has been suggested to play an essential role so that the aim of this study was to investigate the expression and characteristics of Th17 cells as well as the presence of Th17 inducing antigen presenting cells (APCs) in azoospermic testis with chronic inflammation (ATCI) compared with normal spermatogenesis. By stereological analysis, we detected base line expression of Th17 cells in Con. However, increased expression intensity and number of Th17 cells and their cytokines [interleukin (IL)-17A, IL-21, IL-22] and a decreased level of Foxp3+ and interferon-γ+ cells could be demonstrated in ATCI. Moreover, along with these data, increased numbers of Th17-inducing IL-23 producing CD11c+ and CD68+ APCs could be detected in ATCI. From these data, a picture emerges that Th17 cells orchestrated by IL-23 producing APCs are critically involved in chronic inflammation in ATCI.