Previous studies have shown that variation in the distribution of vectors associated to the transmission of Leishmania species may be related to climatic changes. However, the potential implications of these ecological changes in human health need to be further defined in various endemic populations where leishmaniasis carries a substantial burden of disease such as in Northeastern Colombia. Herein, we report the impact of El Niño Southern Oscillation climatic fluctuations during 1985-2002 in the occurrence of cases of leishmaniasis in two northeastern provinces of Colombia. During this period, we identified that during El Niño, cases of leishmaniasis increased, whereas during La Niña phases, leishmaniasis cases decreased. This preliminary data show how climatic changes influence the occurrence of leishmaniasis in northeastern Colombia and contributes to the growing body of evidence that shows that the incidence of vector-borne diseases is associated with annual changes in weather conditions.