PURPOSE: The purpose of this prospective study was to compare the satisfaction levels of the patients worn implant supported mandibular overdentures and conventional complete dentures. MATERIALS AND METHODS: Full edentulous patients (n=40) who were planned to do implant supported mandibular overdentures, aged 51 to 82 years, were enrolled in this study. All subjects rated their satisfaction levels (mastication, pronunciation, esthetics, pain, and general satisfaction) of their original conventional dentures prior to treatment and their new overdentures 1 week and 12 weeks after the delivery on 10 cm visual analogue scales. Repeated-measures ANOVA was performed to compare the satisfaction level of each three period (P<.05). RESULTS: The mean satisfaction levels of the implant supported overdentures after 1 week and 12 weeks of delivery were significantly higher than those of the conventional complete dentures in all scoring parameters (P<.05). After 12 weeks of overdenture delivery, the increase of the satisfaction levels in mastication, pronunciation, and pain and the decrease in esthetics and general satisfaction were observed in comparison with those after 1 week of delivery, however, no significant difference was found between the satisfaction levels of 1 week and 12 weeks after delivery. CONCLUSION: An implant supported overdenture might be one of the effective ways to give more satisfaction to patients who were not gratified with a conventional denture and eventually to improve their quality of life.