Mesozooplankton collections were made during a one-year field period from August 1998 until July 1999 in Kongsfjorden, Svalbard, Norway, to investigate the seasonality of species composition, abundance, stage and vertical distribution. These data provide the first year-round zooplankton observation in Kongsfjorden. Sampling was carried out in the deepest accessible part of the fjord, weather ... permitting. Stratified samples were taken from bottom to surface (if weather conditions allowed: at depthclasses of 0 to 50 m, 50 to 100 m, 100 to 200 m, 200 to 300 m, 300 to 350 m), and were collected with a modified Apstein closing net (0.2 m2 mouth opening, 100 µm mesh).Sampling occurred either from R/V Jan Mayen (University of Tromsø vessel), a Norwegian coastguard vessel (R/V Lance), R/V Oceania (Polish Academy of Science, Sopot), a rubber dinghy, or from the ice through a drilled hole. Except onboard R/V Jan Mayen and R/V Oceania a hand-operated whinch was used for the net hauls. Depth, temperature and salinity were measured at each sampling event. Zooplankton abundance was dominated by North Atlantic and epipelagic species such as Calanus finmarchicus, Psdeudocalanus minutus and Oithona similis indicating a strong influence from the North Atlantic current as well as fjord characteristics.