In various tumor types dentritic cell, infiltration and the presence of tumor-infiltrating lymphocytes have been associated with an improved clinical outcome. In the uterine cervix these immunocompetent cells have been associated with improved prognosis in high stage disease. The current study examines the significance of stromal and tumor T-lymphocyte infiltration together with S-100 positive dendritic cell infiltration in a series of 73 women with low stage (FIGO 1b) invasive squamous and adenosquamous cervical carcinoma. Thirty four percent of cases contained S-100 positive dendritic cells. These were under-represented in cases showing pelvic recurrence or distant disease (1 of 11 compared to 24 of 62 free of recurrence, P = 0.05) and over-represented in cases showing lymphatic/capillary space involvement (12 of 23 compared to 13 of 46 without vascular space invasion, P = 0.05). The women were followed up for an average of 5.2 years and the five-year survival for women whose tumors contained S-100 positive dendritic cells was 92% compared to 73% for negative cases (P = 0.04). There was a significant association between a low density of tumor infiltrating T-cells and risk of pelvic lymph node spread and subsequent local or distant disease control failure (P = 0.008). A five year survival advantage was seen with five or more CD 3 positive tumor infiltrating T-lymphocytes per high power field (90%) compared to a lower count (68%) (P = 0.04). A similar advantage could not be demonstrated for a high stromal infiltrate of T-cells. As yet neither the specific mechanisms that induce these cells to infiltrate some cervical carcinomas nor the nature of the immunological injury that the cells co-ordinate in tumor tissue are well understood.