The microscopic appearance of brown stain occurring in specimens of Tsuga heterophylla (Raf.) Sarg. and Abies amabilis (Dougl.) Forbes after kiln-drying was investigated. Stain was most evident in the sapwood, particularly in the earlywood. The majority of the stain was in longitudinal tracheids, either filling the cell lumen or lining the inner cell wall. However, some stain occurred in the rays. Little or no stain was observed within the cell walls.