Adenomatoid tumors (ATs) are uncommon benign mesothelial tumors with a predilection for the genital tract. We reviewed 47 ATs diagnosed at our institutions during 10-year period. Thirty tumors (64%) originated in the female (21 uterine, 8 tubal, and 1 ovarian) and 17 (36%) in the male (9 epididymal and 8 testicular) genital tract. The median age for females and males was 47.5 and 51 years, respectively. While 83% of tumors in females were incidental findings in resections for unrelated diseases, 94% of male lesions presented as clinical masses leading to surgery. The median size was 2, 1, and 0.5 cm for uterine, epididymo-testicular, and tubo-ovarian lesions, respectively. Architecturally, the microcystic/angiomatoid pattern was the most frequent (32/47; 68%), followed by combined microcystic/trabecular (26/47; 55%) and retiform/adenoid (15/47; 32%) pattern. The trabecular/solid (6%) and macrocystic (4%) patterns were uncommon. However, 57% of cases revealed ≥2 growth patterns. Taken by anatomic site, 20 of 21 uterine cases were at least focally microcystic but none was retiform. In contrast, the retiform pattern dominated in male genital tract tumors (12/17; 71%). Immunohistochemistry showed expression of calretinin (36/36) and D2-40 (30/30) and lack of CD34 (0/30) and PAX8 (0/32). GLUT-1 was expressed in 11/11 male genital tract tumors but in none of the microcystic uterine lesions. Estrogen and progesterone receptor expression was weak and focal (two and three uterine cases, respectively). None stained for the androgen receptor. Our study illustrates the great site-specific morphological diversity of ATs emphasizing their wide site-dependent differential diagnosis.