Inactivation of Escherichia coli O157:H7 and Salmonella typhimurium was evaluated on inoculated chicken by aqueous chlorine dioxide ($CIO_2$) treatment. Chicken samples were inoculated with 6-7 log CFU/g of Escherichia coli O157:H7 and Salmonella typhimurium, respectively. The chicken samples were then treated with 0, 50, and 100 ppm of $CIO_2$ solution and stored at $4{pm}1^{circ}C$. Aqueous $CIO_2$ treatment decreased the populations of the pathogenic bacteria on the chicken breast and drumstick. In particular, 100 ppm $CIO_2$ treatment on the chicken breast and drumstick reduced Escherichia coli O157:H7 and Salmonella typhimurium by 1.00-1.27 and 1.37-1.44 log CFU/g, respectively. Aqueous $CIO_2$ treatment on the growth of the bacteria was continuously in effect during storage, resulting in the decrease of the populations of Escherichia coli O157:H7 and Salmonella typhimurium. These results suggest that aqueous $CIO_2$ treatment should be useful in improving the microbial safety of chicken during storage.