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-3 cruise (spring 1998) with 52 CTD profiles plus associated water bottles samples. Data sets are delivered in both netcdf and ODV formats.