The lichen genus Lepraria in Poland, comprising 17 species, is reviewed: for each taxon, remarks on the chemistry, distribution and habitat preferences are provided. Distribution maps are also presented, together with a key for determination of the Polish species. Lepraria diffusa var. chrysodetoides is reduced to a synonym of L. diffusa s. str., a new chemotype with a new substance is reported for L. neglecta, and rangiformic acid is reported for the first time for chemotype III of L. caesioalba. Lepraria borealis is reported for the first time from Africa (Canary Islands) and L. nigrocincta from Nepal.

The new lichenicolous hyphomycete, Monodictys epilepraria, is described from thalli of several Lepraria species. It is known from the Czech Republic, Great Britain, Lithuania, Poland, Spain and Sweden, and appears to be widespread, but probably much overlooked. The new species is characterized by relatively small, brown, muriform, smooth-walled conidia developing on decolourized patches of the host.

Lepraria aurescens and Lepraria pulchra are described as new from bark in Thailand; both contain thamnolic acid, but differ in thallus form and colour.