Background and Aim: Although tooth loss is associated with varying degrees of reduced quality of life, factors such as the type of prosthesis can affect the quality of life. Therefore, the aim of this study was to evaluate the oral health related quality of life in patients treated with complete dentures and implant-supported over dentures. Materials and Methods: In this cross-sectional descriptive- analyticalstudy,45patients treated with complete dentures and 45patients with implant-supported over dentures who were treated at the prosthetics department of Yazd Dental School between 2012-2020,were selected through convenience sampling and analyzed. Data were collected using the Oral Health Impact Profile (OHIP-14) questionnaire along with demographic variables (age, gender, duration of prosthesis use, number of implants and type of attachment). The data were analyzed using SPSS software version 25 and statistical tests including Mann-Whitney, Kruskal-Wallis, and Spearman's correlation coefficient. Results:The median score of oral health related quality of life in patients with complete prosthetic was 7 and in patients with implant-supported over denture was 1, this difference was statistically significant (P-value < 0.001).There were statistically significant differences in the physical discomfort, psychological discomfort, and physical disability domains between the two groups of patients (P-value <0.05). There was no statistically significant difference in the median scores of oral health related quality of life of the two groups of patients based on age, gender, duration of prosthesis use, number of implants and type of attachment (P-value <0.05). Conclusion: Patients with implant-supported over dentures had a higher oral health related quality of life than those with complete dentures particularly in the domains of physical discomfort, psychological discomfort, and physical disability.