泌尿外科是专门研究男女泌尿系统与男性生殖系统的一门医学，是从外科学细分而来的下属专科。男性的泌尿与生殖系统密不可分，而女性的泌尿道则开口于外阴部。无论男女，泌尿道与生殖道息息相关，两者的疾病常会互相影响。泌尿科学涵盖的器官包括肾脏、输尿管、膀胱、尿道，以及男性生殖系统的睾丸、附睾、输精管、精囊、前列腺、阴囊与阴茎。

泌尿科的专家能治疗以上器官的「内科疾病」（意即不需外科手术治疗者），如泌尿道感染；同时也能治疗其「外科疾病」，如先天畸形的矫治、癌症的手术治疗等。接受泌尿外科治疗的患者只有20％左右需要手术。

Urology (from Greek οὖρον ouron "urine" and -λογία -logia "study of"), also known as genitourinary surgery, is the branch of medicine that focuses on surgical and medical diseases of the male and female urinary tract system and the male reproductive organs. The organs under the domain of urology include the kidneys, adrenal glands, ureters, urinary bladder, urethra, and the male reproductive organs (testes, epididymis, vas deferens, seminal vesicles, prostate, and penis).