Sporocarps of Arcangeliella borziana, a hypogeous russuloid fungus, were found in a subalpine spruce forest in the Swiss Alps. We identified the ectomycorrhizas formed by this species using the ITS-PCR-RFLP method and described them in terms of morphological, anatomical, and molecular features. Phylogenetic placement of A. borziana was studied by comparing nucleotide sequences of the mitochondrial large subunit rRNA gene and the ITS region of nuclear rRNA, respectively, with existing sequence databases, and by comparing the ITS-RFLP pattern with a reference library of approx. 180 mainly basidiomycetous fungi. Sequence analysis of the mitochondrial large subunit rRNA gene confirmed the affiliation of A. borziana to the Russulaceae. Sequence as well as RFLP pattern comparison of the ITS region revealed a close affinity of this species to Lactarius sect. Russularia. This is in accordance with morphological and anatomical studies of the ectomycorrhizas, which share many features with ectomycorrhizas of Lactarius sect. Russularia.