Aim of the study: To compare the effect of two different relief techniques on the stability of maxillary complete dentures. Materials and methods: Ten completely edentulous patients received one mandibular and two maxillary complete dentures. One was directly relived by building up tin foil on the master cast (denture A) and the other was automatically relieved using the selective pressure impression technique (denture B). Patients were allowed to function with each denture for three months separated by an interval of two weeks. Stability was measured by a specially designed stability and retention testing device at time of denture insertion, one month and three months later. Paired t-test was used to detect significant differences between both denture groups and to study the effect of time on the stability. Results: A significant difference between the stability values recorded for dentures (A) and (B) was found at time of insertion, one month and three months of denture insertion. The stability of both dentures increased significantly throughout the study period. Significance level was set at p≤ 0.05. Conclusion: Although the stability of both dentures increased by time, maxillary dentures which were made by automatic relief showed stability higher than that which made by building up tin foil on the master cast.