A retrospective analysis of the CT examinations of 45 patients with squamous cell carcinomas of the tongue, floor of the mouth and tongue base with long-term follow-up is presented. The aim of the study was to determine whether differences in tumor contrast enhancement and tumor demarcation at contrast-enhanced CT were correlated to prognosis in terms of posttreatment residual tumor or local recurrence. Ill-defined tumor margins were by means of multiple regression analysis significantly correlated to local failures (p = 0.043). This feature was, however, not associated with a significant decreased survival. The degree of tumor contrast enhancement did not parallel variations in the histopathologic composition of the tumors.