this work evaluated the effect of gamma radiation on reducting the population of staphylococcus aureus, escherichia coli and salmonella typhimurium in ground chicken breast stored under refrigeration. the experiment included a control and 4 doses of gamma radiation (2.0, 4.0, 6.0 and 8.0 kgy) along with 5 periods of storage under refrigeration (1, 7, 14, 21 and 28 days). samples of ground chicken breast were inoculated with staphylococcus aureus (atcc 14458), escherichia coli (atcc 11105) and salmonella typhimurium (atcc 0626), irradiated at temperatures between 4 and 8°c and stored under refrigeration (5°c) for 28 days. the increased radiation dose and period of storage under refrigeration caused a reduction of staphylococcus aureus, escherichia coli and salmonella typhimurium populations in the ground chicken breast. mean radiation d values determined for staphylococcus aureus and escherichia coli were 0.41 and 0.72 kgy, respectively. gamma irradiation was an effective treatment for chicken meat conservation because the radiation dose of 6.0 kgy kept the ground chicken breast within the microbiological limits established by the brazilian legislation, for up to 28 days under refrigeration.