Ectopic adrenal rests are a rare condition which can be found in various sites, generally in the retroperitoneum or pelvis along the path of gonadal descent. Their real prevalence is unknown. Males are more commonly affected, at least in the pediatric age. Adrenal rests are usually clinically silent and incidentally found in surgical samples, mostly in the pediatric population, and rarely in adults. With the aim of increasing knowledge and estimating the prevalence of ectopic adrenocortical tissue in the adult population, 44 adrenal rests in the urogenital tract of 40 adults are described. These represent approximately 0.07% of the total number of urogenital and gynecological surgeries performed in the 22 considered years. Adrenal rests were identified in the spermatic cord (10 males) and in paraovarian, parasalpingeal, or infundibulopelvic ligament locations (30 females). All but one was incidental findings. One case regarded an adrenocortical carcinoma arisen in adrenal rests. A literature review of adrenal ectopia in the urogenital tract of adults identified 57 reported cases from 53 patients, with similar clinicopathological features as those of our series, with the exception of a lower incidence of parasalpingeal locations. Despite their limited clinical implications, awareness of ectopic adrenal rests is essential also in adults for at least two reasons: (a) to correctly identify sources of adrenocortical hormone production in case of adrenal insufficiency or hormonal imbalance and (b) to avoid misinterpretations in the diagnostic workup of renal cell carcinoma, adrenocortical tumors, and rare gonadal neoplasms, including Sertoli/Leydig cell tumors.