Three cases of primary papillary serous adenocarcinoma of the uterine cervix, the first described in detail at this site, are reported. Two women, 32 and 33 years of age, presented with postcoital spotting. The third patient, a 69-year-old asymptomatic woman, had abnormal cells on a routine cervical Papanicolaou smear. There was no evidence of extracervical spread on physical examination in any of the cases, but computed tomographic scan of the abdomen revealed retroperitoneal lymphadenopathy in one patient. Two patients, one treated by preoperative radiation and cervicectomy and the other by radical hysterectomy and postoperative radiation, are alive and well 5 years later. The third patient underwent cone biopsy and is currently completing chemotherapy to be followed by radiation therapy. On gross examination, the tumors were indistinguishable from typical endocervical adenocarcinoma. Microscopic examination revealed high-grade papillary serous adenocarcinoma in each case; in one tumor, there was a minor admixed component of low-grade villoglandular papillary adenocarcinoma. Although none of the tumors was deeply invasive, pelvic nodal metastases were present in two cases. There was no evidence of endometrial, tubal, ovarian, or peritoneal tumor in any case. Papillary serous carcinomas should be distinguished from other papillary carcinomas of the cervix, particularly the recently described low-grade papillary villoglandular adenocarcinoma, a variant of endocervical adenocarcinoma with a good prognosis.