Salivary leakage can be a major symptom of valve failure or incorrect positioning of indwelling voice rehabilitation valves in a tracheo-oesophageal fistula. Usually, removal of the valve for a short time leads to shrinking of the fistula or a simple valve replacement procedure resolves the problem. If the fistula, however, does not close spontaneously, symptoms persist and the fistula may have to be closed surgically. In a retrospective study, data of 103 patients who underwent laryngectomy and primary voice rehabilitation between 1989 and 1998 with either the Provox or the Eska-Herrmann prosthesis were compared with regard to surgical fistula closure requirement. A total of 55 patients underwent laryngectomy and primary voice rehabilitation with the Eska-Herrmann and 48 with the Provox prosthesis. Initial tumour treatment also included post-operative radiotherapy for all patients in the study. In total, surgical fistula closure had to be performed in three patients, all of whom had been treated with the Provox prosthesis. The time span between initial voice rehabilitation and surgical closure of the fistula was 5 months, 21 months and 24 months in all three patients respectively. None of the fistulas developed in relation to recurring tumour disease. The Provox prosthesis seem to have a higher risk of developing fistulas necessitating surgical intervention, even years after initial tumour therapy, than the Eska-Herrman prosthesis. These complications may be due to the larger tracheo-oesophageal fistula necessary to fit the larger diameter of the Provox prosthesis.