In four mountain aquatic ecosystems of altiplano Cundiboyacense, Colombia, we compared through analysis regression data set of chlorophyll-a obtained with spectoropho-tometric (tricromatic formula) and fluorometric (Welschmeyer) methods. The analysis showed that the spectrophotometric method overestimated the chlorophyll-a concen-tration, but it could be used with precaution in the lower trophic environments. An equation that relates the two chlorophyll-a measures was obteined.