The recent mountain pine beetle (Dendroctonus ponderosae Hopkins) epidemic has affected millions of hectares of conifer forests in the Rocky Mountains. Land managers are interested in using biomass from beetle-killed trees for bioenergy and biobased products, but they lack adequate information to accurately estimate biomass in stands with heavy mortality. We destructively sampled live (n = 7) and mountain pine beetle-killed (n = 7) lodgepole pine (Pinus contorta Dougl. ex Loud.) trees in the northern Colorado Rocky Mountains to develop and compare diameter-based aboveground component biomass equations. We used the seemingly unrelated regression approach to simultaneously estimate the parameters in the system of allometric equations. The results show no significant difference in total aboveground biomass between live and dead trees. However, top, bark, and foliage components are significantly different between the two groups (P < 0.05). When logging residues (i.e., tree tops, branches, and foliage) are of interest as biomass feedstock, the allometric equations developed for beetle-killed trees could provide more accurate estimates of the resources available in beetle-killed stands than the existing live tree allometric equations.