The Eddies and Leddies Interdisciplinary Study in the Algerian sub-basin (ELISA) experiment (1997–1998) was a multidisciplinary and multiplatform experiment designed to study the anticyclonic Algerian Eddies (AEs) generated by the instability of the Algerian Current, and their influence on the general circulation and biological phenomena. The data collected confirmed for instance the eastward path of LIW along the Algerian slope, and showed that these anticyclones correspond to the richer areas in spring. Following the daily analysis of satellite thermal images to track the AEs, the sampling scheme was adapted in real time, using transects with CTD casts every ~10km. So that the data are strongly "biased" toward describing (moving) eddies at high resolution: they are likely to be unadequate for a few purposes. The ELISA hydrological data sets have been obtained during the four cruises ELISA-1 to 4, from summer 1997 to summer 1998. This data set includes the ELISA-1 cruise (summer 1997) with 199 CTD profiles on 121 stations plus associated water bottles samples, and the  ELISA-2 cruise (fall 1997) with 6  CTD profiles. Data sets are delivered in both netcdf and ODV formats.