Parent and preflight-adult Douglas-fir beetles (DendroctonuspseudotsugaeHopk., Coleoptera: Scolytidae) were collected from felled Douglas-fir (Pseudotsugamenziesii(Mirb.) Franco) trees. Fungi isolated from the beetles included blue-stain fungi, such asOphiostomapseudotsugae(Rumbold) von Arx,LeptographiumterebrantisBarras & Perry, andLeptographiumabietinum(Peck) Wingfield; other ascomycetes, such asGraphiumspp. andLeptographiumspp.; yeasts; and unidentified basidiomycetes. All fungal cultures derived from parent beetles, preflight adults, beetle eggs, larvae, frass, and bark from galleries had yeasts present.Ophiostomapseudotsugaewas isolated from 67% of the parent females, 19% of the parent males, and 100% of the preflight adults of both sexes collected from their pupal cells. Rinsing the beetles with 70% ethanol prior to fungus isolations reduced the frequency of all fungi, except yeasts. Parent and preflight adult beetles (of both sexes) were examined with a scanning electron microscope, where spores ofO.pseudotsugaewere visible in shallow pits on the elytra of both male and female beetles. Spores of other fungi were observed in shallow pits on elytra and in much smaller but deeper pits on the scutellum of both sexes. The results indicate a close association between Douglas-fir beetles and fungi, accompanied by anatomical differentiation on the beetles that allows the dissemination of blue-stain fungi to new Douglas-fir hosts and substrates.