Phosphatic inarticulate brachiopods are described from Middle Ordovician (Viru Series) strata in Västergötland and Dalarna, Sweden. The material orginates from a series of closely spaced samples through the sequences of the Fjäcka and Kargärde sections, Dalarna, and at Gullhögen quarry, Västergötland. Fifty-six species (34 named, of which 22 are new) are described, assigned to 29 named genera (of which three are new). The new acrotretacean subfamily Biernatinae is proposed, together with the new acrotretacean genera Cyrtonotreta and Biernatia; the problematic genus Tegulella is erected. For the discinaceans and most of the lingulaceans open nomenclature is applied. The evolution of the phosphatic-shelled inarticulates is discussed. The usefulness of the inarticulates for biostratigraphical correlation is demonstrated.