In a prospective study of 465 patients with invasive carcinoma of the uterine cervix, the prognostic impact of flow cytometric parameters (ploidy level and fraction of S-phase cells) and clinical variables was evaluated. Median follow-up time was 57 (32-80) months. A total of 230 patients died of cervical cancer during follow-up. Ploidy level had no prognostic significance, neither when analyzed as diploid against nondiploid nor when utilizing different cutoff levels for DNA index (1.3, 1.5, and 1.7). The fraction of S-phase cells (SPF) could be evaluated in 91% of the diploid cases but in only 22% of nondiploid cases. SPF had no prognostic impact. In multivariate analysis, FIGO stage was the only independent prognostic factor (P < 0.001). There was no difference between squamous cell, adeno, and adenosquamous carcinomas. A radical hysterectomy with pelvic lymphadenectomy was performed in 123 cases in stage I-IIA. In this subgroup, tumor size (P = 0.001), infiltration into the parametria (P = 0.005), vessel invasion (P = 0.008), and metastasis to the common iliac nodes (P = 0.013) obtained independent statistical significance in multivariate analysis, while ploidy level had no significance. Neither DNA ploidy nor S-phase analyses should be used in treatment planning.