Abstract Aim Open reduction and internal plate fixation of the fibula is the gold standard treatment for ankle fractures. The aim of this study was to perform a prospective randomized study to compare bone union, complications and functional results of two types of internal fixation of the fibula (plating and the Epifisa® FH intramedullary nail). Materials and methods Inclusion criteria were: closed fractures, isolated displaced fractures of the lateral malleolus, inter- and supra-tubercular bimalleolar fractures, and trimalleolar fractures. This study included 71 patients (mean age 53±19): plate fixation group (n=35) and intramedullary nail fixation group (n=36). In seven cases, intramedullary nailing was technically impossible and was converted to plate fixation (the analysis of this sub-group was performed independently). Two patients died and two patients were lost to follow-up. The final comparative series included 32 cases of plate fixation and 28 cases of intramedullary nail fixation. Union, postoperative complications and Kitaoka and Olerud-Molander functional scores were analyzed after one year of follow-up. Results There was no significant difference in the rate of union (P=0.5605) between the two types of fixation. There were significantly fewer complications (7% versus 56%) and better functional scores (96 versus 82 for the Kitaoka score; 97 versus 83 for the Olerud-Molander score) with intramedullary nailing than with plate fixation. Conclusion Intramedullary nailing of the lateral malleolus in non-comminuted ankle fractures without syndesmotic injury is a reproducible technique with very few complications that provides better functional results than plate fixation. Level of evidence II (randomized prospective study).