Purpose: This study aimed to evaluate the effect of microwave disinfection protocol on dimensional changes and the pattern of occlusal pressure over lined complete dentures. Material and methods: ten completely edentulous patients were selected to receive conventional complete dentures. A layer of soft liner was added to the lower dentures and occlusal pressure contacts were recorded using T-scan device. The lower dentures were subjected to microwave radiation 700 Watt for three minutes once a week for four successive weeks in a dry condition. Twenty maxillary denture bases were constructed and lined with soft liner, the gap between the lined denture base and the stone cast was measured at the posterior palatal seal area at three different points, as well as the occlusal pattern before and after exposure to microwave radiation. Results: there were no significant effect for using microwave radiation on the lined denture regarding occlusal force distribution and dimensional changes. Conclusion: lined denture disinfection by microwave energy at 700watt for three minutes has no statistically significant effect over the dimensional changes and occlusal force distribution