The Prados-Scott model for coated-particle behavior has been modified to include the effects of irradiation-induced creep on the stress-strain history of pyrolytic-carbon coatings. Calculations are performed in a stepwise fashion, with double trial-and-error iterations required for each time (or fluence) increment. Lack of accurate information on the mechanical behavior of pyrolytic carbons under irradiation still limits the quantitative applicability of the results; however, the computational sequence has been designed to permit simple updating of mechanical behavior subroutines as more reliable data are obtained. Using the best available creep information, we found that the performance of typical pyrolytic-carbon-coated particles is significantly improved by creep under conditions of irradiation which will obtain in advanced high-temperature gas-cooled reactors. On the other hand, with the high burnup rates and low fast fluences characteristic of most coated-particle proof tests, the effects of creep are small and are likely to be undetectable. In such cases, an elastic model can be used effectively to predict failure.