The clinical and histologic features of 476 tumors fitting the 1995 FIGO definition of stage IA cervical cancer, treated at a Sydney tertiary referral hospital between 1953 and 1992, are reviewed. Five-year follow-up was complete with a median of 10 years. The diagnosis was increasingly made by histologic examination of colposcopically directed cone biopsy. The majority (88%) of tumors were squamous. The proportion of both younger women (</=35 years) and adenocarcinoma and adenosquamous tumors increased during the second half of the study. Nearly half invaded 1 mm; a third 1.1-3 mm and 20% 3.1-5 mm. Lymph vascular space invasion (LVSI) increased with increasing depth of invasion and was present in over half the tumors invading >3 mm. Treatment was surgical in 99% and was increasingly more conservative as the study progressed with no apparent increase in treatment failure. From 1973 treatment by cone biopsy rose from 6.5 to 35%, by radical hysterectomy fell from 51 to 21% and by lymphadenectomy from 53 to 26%. Only one of 115 patients treated by cone biopsy died. Positive lymph nodes were detected in 1.7% of 180 patients undergoing lymphadenectomy. There were 16 recurrences (3.4%); six vaginal with no cancer deaths, nine pelvic and one distant, with nine deaths and three new cancers (two deaths). Univariate analysis suggests that older age, glandular tumors and those invading 3 mm were associated with more treatment failures and multivariate analysis showed that both conservative hysterectomy and the omission of lymphadenectomy are associated with higher recurrence rates with >3 mm invasion. The study failed to resolve the dilemma of predicting those tumors with a poor prognosis.