dendrochronology provides hydroclimatic proxy records in many regions with scarcity of instrumental records. In this paper, we reconstructed the Low Atrato Rivers water levels and assessed the effect of the ENSO phenomenon in the river level over the past 150 years using the tree rings of Prioria copaifera tree (Cativo). We demonstrated the annuality of the growth rings by 14 C, and by correlations with annual climatic variables. To reconstruct river levels, we used 23 ring width series, and standard dendrochronology methods to cross- dating, detrending, standardize the series, remove the serial autocorrelation, and calculate both Arstan and Residual chronologies. We found positive and significant association ( r=0,589; p<0,01) between water levels and Cativo's growth. Residual chronology Cro4R correlated significant and positively with SOI, and the opposite with ONI of ENSO. We found no statistical significant effect on the trend of the Atrato River levels over the past 150 years.