This paper initiates a series of publications on the morphology of the dialect of Staroshvedskoye (Sw. Gammalsvenskby), which is the only surviving Scandinavian dialect on the territory of the former Soviet Union. The village of Staroshvedskoye is located in the Kherson region, Ukraine. Its Swedish dialect historically belongs to the group of Swedish dialects of Estonia and goes back to the dialect of the island of Dagö (Hiiumaa). The dialect of Gammalsvenskby is of interest to slavists as an example of a language island in the Slavonic environment. From around the 1950s, the main spoken language of all village residents, including dialect speakers, has been surzhik. Due to the complete lack of studies of the present-day dialect and because of the severe endangerment in which the dialect is currently situated, the most urgent task is to collect, classify and publish the factual material. This paper introduces comprehensive material on nouns in the conservative variety of the present-day dialect. It lists all masculine nouns of type 1a together with their cognates from Estonian Swedish dialects; comments on the history of the forms are given as well. The sources for the material presented here are interviews with speakers of the conservative variety of the dialect recorded by the author during fieldwork in the village from 2004 to 2012. We plan to publish nouns of other types in later articles.