Chukchi Sea benthic ostracode assemblages collected during a research cruise aboard the USCGC Healy in 2017 are compared to collections from past years, primarily 2009 and 2010, with a goal of understanding recent species changes related to temperature, total organic carbon (TOC) and sediment grain size. The study area includes the continental shelf region influenced by the Alaska Coastal Current and the northward extension of the Bering Sea Shelf waters that flow through Bering Strait. Significant temporal (decadal, interannual) and spatial variability in the proportions of dominant species in the assemblage were observed, including an increase in subarctic species, particularly, Normanicythere leioderma, which is typically dominant in the Bering Sea, but which showed a notable range expansion in 2017 into the Chukchi Sea (20% of the 2017 Chukchi Sea assemblage). Secondary subarctic species with increasing abundance include Schizocythere ikeyai (8%) and Munseyella kiklukhensis (7%). A corresponding decline in dominance of Paracyprideis pseudopunctillata (4%), a common Arctic species in Chukchi, Beaufort and Laptev Sea assemblages, is another significant change. Continued monitoring of temperature-sensitive ostracode species in the Bering and Chukchi Seas is planned to provide additional information on annual and decadal variability in species dominance.