The effects of gamma irradiation on microbial quality, lipid oxidation, and sensory characteristics of meatballs were studied, and these effects were compared with the effects on ground beef. Meat samples were irradiated at 0, 3, 6, and 9 kGy, then stored at 4 +/- 1 degrees C for 14 days. Irradiation resulted in greater microbial inactivation, lower lipid oxidation, and less adverse effects on sensory characteristics in meatballs compared to ground beef. Irradiation of meatballs at 3 kGy resulted in about a 4-log reduction in total microbial count without significantly affecting the quality of the product during the first 3 days of storage. Higher doses or longer storage in air resulted in quality degradation, which could be controlled by proper modified atmosphere packaging (MAP). Thus, irradiation doses approved for ground beef can be safely used with meatballs without significant quality degradation. Further studies combining irradiation and MAP are needed to determine the shelf- life of irradiated meatballs.