Abstract The time series of water level of Titicaca Lake (TL) was compared to the time series of the Pacific Decadal Oscillation (PDO) and El Niño/Southern Oscillation (ENSO) indexes between 1914 and 2014 and 1969 and 2014, monthly and daily, respectively. Results indicate TL water level decreased (increased) during positive (negative) PDO phases. ENSO positive (negative) phase results were similar. Positive (negative) PDO and ENSO phases yielded negative (positive) precipitation anomalies and concomitant decrease (increase) of TL water level. These long-term relationships among TL water levels and both oceanic indexes can be useful and prognostic.