The distribution and abundance of four zooplanktonic groups were evaluated over the periods June and October 1996 (La Niña: LN) and May and December 1997 (El Niño: EN). Their order of abundance was: chaetognaths, thaliaceans, euphausids and planktonic polychaetes. The most important genera were: Sagitta (Chaetognatha), Thalia and Weelia (Thaliacea), Euphausia (Euphasiacea), and Maupasia. coeca, M. isochaeta, Plotohelmis capitata, and Vanadis crystallina (Polychaeta). Within chaetognaths, Eukrohnia is the first report for the Colombian Pacific. The spatial distribution of the four groups most likely was associated with hydrological dynamics, especially in areas where fertilization processes took place. LN 1996 offered better conditions for the development of all groups especially in October. Their marked diminish in 1997 is explained by the increase of temperature caused by EN.