We evaluated the effect of microwave irradiation on soft contact lens parameters to determine if microwave disinfection affects soft lens polymers or parameters. Ten factory sealed lenses from each of the four FDA categories were placed in Ciba AOsept cases and filled with 13 ml of sterile unpreserved saline. The cases were placed in a 10 cm diameter circle on the rotating plate of a standard 2450 MHz 650 watt microwave oven and exposed to five minute cycles of microwave irradiation. The lens parameters, including back vertex power, back central optical radius, diameter, front surface sag, thickness, and water content, were measured over a period of 200 cycles to simulate over six months of daily disinfection. The post irradiation measurements were compared to the base line measurements taken prior to microwave exposure. We found changes in one or more parameters of all four lens categories. While the changes were statistically significant, they were small and generally not considered clinically significant. These findings indicate that microwave disinfection may be a viable alternative to current methods of soft contact lens disinfection.