Fourteen species of stromatic pyrenomycetous fungi (family Xylariaceae) collected in northern Thailand are discussed. Six of these (Biscogniauxia lithocarpi, Camillea malaysiensisvar.macrospora, Hypoxylon juventuterubrum, H. pseudoretpela, H. rubroargillaceum, and H.sepipigmentum) are described as taxa new to science