A phylogenetic study of the lichen family Graphidaceae is presented. Most genera of the family, as well as selected representatives of the closely related Thelotremataceae, are included. The results of the Bayesian analysis of combined mt SSU and nuLSU rDNA sequence data were compared with recently introduced concepts of genera. Species of Fissurina and Dyplolabia form a monophyletic group in an unresolved sister-group relationship to other members of Graphidaceae and Thelotremataceae. The family Graphidaceae as currently circumscribed is paraphyletic and we suggest that the name Graphidaceae is used in a broader sense to include members of Thelotremataceae. The concepts of Glyphis, Phaeographis and Platygramme are confirmed by molecular data. Surprisingly, Graphis species are found in two distinct clades, which can only partly be explained by morphology. Hemithecium as recently circumscribed is polyphyletic: H. implicatum, with hyaline spores groups within the Graphis scripta clade, whereas a second Hemithecium species, representing subgenus Leucogramma with brown spores, forms a well-supported clade with other brown-spored species such as 'Sarcographina'lyphiza, Leiorreuma hypomelaenum and Sarcographa ramificans. The evolutionary pattern of morphological characters of the ascomata such as exciple carbonization, paraphyses types, and ascospore characters (colour, septation, and Lugols reaction) are critically discussed.