Technical Abstract: A precise, reproducible microassay was developed to measure thermal inactivation of high pathogenicity avian influenza (HPAI) virus in chicken meat. Small pieces of breast or thigh meat (0.05 g) from chickens infected with A/chicken/Pennsylvania/1370/1983 (H5N2) (PA/83) or A/chicken/Korea/ES/2003 (H5N1) (Korea/03) HPAI viruses were tested for inactivation in a heat block system of a thermocycler. Korea/03 infected thigh and breast meat had higher virus concentrations (6.8 log 10 and 5.6 log 10 mean embryo infectious doses [EID50]/g, respectively) compared to PA/83 infected thigh and breast meat (2.8 log 10 and 2.3 log 10 EID50/g, respectively). The samples were ran through a ramp-up cycle from 25-70C, and samples were removed and examined for virus infectivity at 30, 40, 50, 60 and 70C, and after treatment for 1, 5, 10, 30 and 60 s at 70C. The reduction in virus infectivity titers was dependent on virus concentration and no HPAI virus was isolated after 1 s of treatment at 70C. A change in coloration from pink-tan to white was associated with a loss in recovery of infectious virus. The microassay provided a predictable and reproducible method to measure thermal inactivation of HPAI virus in chicken meat.