Background.- Resection of tumors infiltrating the floor of the mouth or adjacent areas cause complex reconstructive problems because of the anatomic and functional properties of the region. Reconstruction of .the floor of the mouth should allow free movements of the tongue and should maintain the continuity of the mandible in order to preserve normal speech, swallowing and digestion. Design.- Twenty patients with malignant tumors infiltrating the floor of the mouth were treated between 1990 to 1995. The mandible was also invaded in 13 cases. In 6 cases unilateral and in 3 cases bilateral neck dissection was performed during tumor resection. Reconstructions were done in the same stage in all cases except the one reconstructed with bilateral nasolabial flaps. Pedicled myocuta-neous flaps (Lattissimus dorsi, Pectoralis major, Trapezius) in 4 cases, local flaps (frontal flap, bilateral nasolabial flaps, tongue flap) in 3 cases, free flaps (radial forearm, scapular, DCIA flap) in 7 cases and a sequentially linked free flap (vascularized fibula and radial forearm fasciocutaneous flaps) in one case was used for the reconstruction. Results.- Early postoperative complications were mandibular fracture in one case, temporary salivary fistula in 2 cases and limited wound dehiscence in one case. One case died because of aspiration pneu¬monia 12 days after the operation. Local tumor recur¬rence was observed in 2 cases and one of them died due to intracranial tumor infiltration. Conclusion.- Free tissue transfers with microvas-cular surgical technique started a new era in the reconstruction of the floor of the mouth. Pedicled flaps can be used when bulkiness is needed, but free flaps should be used when a thin lining or complex reconstruction is necessary.