Background Infertility continues to be a highly prevalent condition. Although assisted reproduction technology has been significantly effective, it is relatively costly and may yield disappointing clinical outcomes. There is still an unexplained correlation between the substantial contribution of the testicular somatic cells such as the peritubular cells and interstitial immune cells such as mast cells. Aim The aim of this work was to study the histological, immunohistochemical, and morphometric profiles of peritubular cells and mast cells in azoospermic men that might be a clue for male infertility therapy. Patients and methods This study was carried out on 39 infertile azoospermic men attending the Andrology Outpatient Clinic in Assiut University Hospital. Patients were divided into two groups. Group I (GI), which included patients with obstructive azoospermia (n=9), and group II (GII), which included patients with nonobstructive azoospermia. GII was subdivided as follows: Subgroup A, which included patients with Sertoli cell-only syndrome (n=9); subgroup B, which included patients with germ cell arrest (n=10); and subgroup C, which included patients with hypospermatogenesis (n=11). Testicular biopsies were obtained and processed for light, immunohistochemical, morphometric analysis, and electron microscopic examinations. Results The testicular interstitium of GI showed an apparently normal pattern of organization as regards cellular and fibrous components. GIIA showed the highest mast cell number, which established cytoplasmic projections toward peritubular cells. The mean count of tumor necrosis factor α-positive cells showed a significant increase in GIIA compared with GI. The mean area% of collagen fibers increased significantly in GIIA, GIIB, and GIIC compared with GI. In GIIB, bundles of microfibrils were most evident between the basement membrane and the first layer of peritubular cells. In GIIC, they appeared flattened with slender interlacing processes forming bridges. Mast cells bore long cytoplasmic projections, which extended toward the neighboring fibroblasts. Conclusion The present data signify complex cell interactions in cases of testicular dysfunction within the interstitial compartment.