We surveyed macroalgae at Hansneset, Blomstrand (78°39′N, 11°57′E) in Kongsfjorden, Svalbard, down to 30 m depth between 1996 and 1998. In total, 62 species were identified: 16 Chlorophyta, 25 Phaeophyceae, and 21 Rhodophyta. The majority of species (53.5%) belonged to the Arctic cold-temperate group, followed in frequency by species distributed from the Arctic to the warm-temperate region (25.9%). Four endemic Arctic species ( Laminaria solidungula , Acrosiphonia flagellata , A. incurva , and Urospora elongata ) were found. Two species ( Pogotrichum filiforme and Mikrosyphar polysiphoniae ) were new to Svalbard. Chlorophyta, Phaeophyceae, and Rhodophyta extended from the eulittoral zone down to 11, 21, and >30 m depths with maximum biomasses at 1–5 m, 5–10 m, and 5–30 m depths, respectively. Annual and pseudoperennial species had highest biomasses in the upper 5 m, while perennials were distributed deeper. The highest biomass (8600 g m -2 wet weight) at 5 m depth comprised mainly L. digitata , Saccorhiza dermatodea , Alaria esculenta , and Saccharina latissima . The biogeographic composition of macroalgae at Hansneset was rather similar to that of northeastern Greenland, but different from that of northern Norway, which has a higher proportion of temperate species. Climate warming and ship traffic may extend some of the distribution ranges of macroalgae from mainland Norway to Svalbard.