Silk and cotton fabrics were dyed with Parmelia tinctorium that is a kind of lichen. Dyeing solution was prepared by fermentation in aqueous ammonia solution. The effects of pH and temperature in dyebath on dyeability were investigated. The maximum K/S value of each dyed fabrics was showed in 480nm. Silk fabrics showed better dyeability than cotton. Silk fabrics dyed well in acidic or neutral dyebath at $80^circ{C}$ and cotton fabrics in neutral dyebath at $50^circ{C}$. Both of silk and cotton fabrics showed poor dyeability in basic dyebath because of colouring anionic groups in lichen. The Munsell values of dyed silk fabrics were appeared in R(red) range, and them of cotton fabrics in YR(yellow-red) range. Light fastnesses of dyed fabrics were as poor as 2 or 2-3 grades. Also, Laundering fastnesses of dyed silk fabrics were as poor as 2 grade and those of cotton fabrics were 3 or 3-4 grades. But dry-cleaning fastnesses of all dyed fabrics were good.