The effects of jam processing on total phenolics, total flavonoids, total anthocyanins, and antioxidant capacities of fresh Rubus coreanus Miquel (bokbunja) fruits at various pH levels were investigated. Aqueous methanol of 80%(v/v) was found to be the most efficient solvent for extracting phenolics in fruits and jams. More than 90% of total phenolics, antioxidant capacities, and total flavonoids were retained after processing, while approximately 35% of total anthocyanins were lost. Among various pH treatments, jams prepared at pH 2.0-3.0 lost 33-35% of total anthocyanins, while treatments at pH 3.5-4.0 degraded 40-48% of total anthocyanins. Among the various treatments between pH 2.0 and 4.0, jam prepared at pH 3 had the highest sensory scores and overall acceptability. The results suggest that jam making with fruits rich in anthocyanins at lower pH may protect bioactive anthocyanins from thermal processing.