*Study Objective*: Evaluate sorption and solubility of bulk-fill and conventional resin composites after one-year storage in water and artificial saliva. *Method*: Tested six bulk-fill and eight conventional resin composites by immersing disc-shaped samples in water and artificial saliva for a year and measuring weight at intervals. *Results*: Materials stabilized within three months in water (except X-Flow) with a slower increase in artificial saliva over a year. Most materials showed similar sorption values in water and artificial saliva. Sorption and solubility varied among materials.