INTRODUCTION: The purpose of this retrospective study was to evaluate oncological and functional results after reconstruction of the anterior floor of the mouth using free flaps. METHODS: From 1992 to 1998, 30 patients with squamous cell carcinoma of the anterior floor of the mouth underwent surgical excision and primary reconstruction with either free forearm- or bone-composed flaps. Functional assessment included evaluation by the Karnofsky scale, Performance Status Scale for Head and Neck Cancer (PSS-HNC), articulation test and videofluoroscopic examination. RESULTS: 16 patients underwent reconstruction with a free forearm flap, 13 with an iliac crest flap and 1 with a fibula flap. The most serious local complication was partial flap necrosis in two cases. Local control was 90% at 24 months and the specific survival rate was 92% at five years. Functional evaluation was performed on 19 patients: PSS-HNC median score for diet was 70 (range 50-100), the score for speech was 70 (range 50-100) and the score for "eating in public" was 65 (range 25-100). Patients with a major mobile tongue resection had a lower score compared to patients with minor or no mobile tongue resection. Videofluoroscopy showed swallowing alterations following large resections of soft tissues. DISCUSSION: Our study confirms that wide resection of mobile tongue is associated decreased rehabilitation quality. Mandibulectomy does not influence rehabilitation.