Historically, Annosus root rot (Heterobasidion annosum) has seldom been a problem in Pacific Northwest Christmas tree plantations. During the past three years, the prevalence of this disease has increased significantly in 2nd and 3rd rotation noble and Fraser fir plantings. During 2001, 19 field plots were established to obtain a better understanding of the association of this disease with tree mortality. A total of 23,337 trees were examined for above ground symptoms such as branch flagging, wilting, and death. The percent-age of symptomatic trees in these plots ranged from 2.5 to 13.6%. If missing and replanted trees were included, the maximum percentage reached 29.2%. H. annosum was associated with 78% of the dead and dying trees. Annosus root rot was detected on noble, Fraser, and grand fir, as well as Douglas-fir. Noble and Fraser fir appears to be very susceptible to this disease. These field plots will be monitored during the next several of years to determine the level of mortality prior to harvest