Tagged ponderosa pines (Pinus ponderosa var. scopulorum) were examined at Grand Canyon National Park, AZ, to determine 32-year survival rates in trees with various intensities of dwarf mistletoe (Arceuthobium vaginatum subsp. cryptopodum). Survival was influenced mainly by dwarf mistletoe severity, but also by tree diameter. More than 90% of the uninfected and lightly infected (Dwarf Mistletoe Rating Class 1) trees survived the 32-year study period. However, only 5% of the heavily infected (DMR Class 6) trees over 9 in. dbh, but none of those in the 4-9 in. class, survived the period. The mean longevity, or period during which half the trees are expected to die, for Class 6 trees was 10 years for trees over 9 in. and 7 years for smaller ones; comparable figures for Class 4-5 trees were 25 and 17 years, respectively. West. J. Appl. For. 5(2):47-48, April 1989.