The present paper investigates the interaction of mass nouns with numerals in Russian. While the combination of paucal numerals with morphologically singular mass nouns is often judged by native speakers as acceptable or near-acceptable (e.g., dva supa 'two soups'), plural counterparts of these nouns are systematically unacceptable with non-paucal numerals (e.g., *pjat' supov 'five soups'). The author argues that this unacceptability is due to the fact that pluralization of mass nouns takes place below nP in Russian, while the mass-to-count shift applies at a higher level. Evidence is provided for the low formation of Russian mass plurals that is based on the existence of idiosyncratic gaps and non-compositional meanings. Two types of plural operators are discussed, and it is shown why none of them can create an appropriate input for the application of a mass-to-count operator. In contrast, with paucal numerals, the noun remains singular and allows the (context-sensitive) mass-to-count shift. Mass plurals are also compared to plural nouns containing the singulative suffix -in (e.g., gorošina 'a pea'): the original noun first undergoes a mass-to-count shift, triggered by the suffix, and is then pluralized, which constitutes an appropriate order of operations. A separate section is dedicated to subkind readings of mass plurals.