ABSTRACT: Annatto is a natural dye extracted from the pericarp of Bixa Orellana L. seeds. The main coloring agents of this dye are bixin and norbixin. In this study, it was evaluated the effect of light and temperature on the stability of an aqueous formulation of norbixin. Both studies were carried out in controlled conditions. Photostability studies were conducted exposing samples in different concentrations under irradiated for 6 hours using a xenon lamp at 1000 W/m2. The effect of temperature was assessed by analyzing the samples exposed at 30±2oC during 12 months, in order to simulate the natural storage condition. Norbixin concentration during storage after exposure to various conditions was measured by spectrophotometry at 455 nm. This was correlated with color, which was measured by sensorial analysis, where perceptible changes in color were identified. Results from forced photostability studies showed that samples at high norbixin concentration (5.58%) did not suffer decomposition. The decay of norbixin promoted by temperature was fitted a linear model, and a significant change of color was observed at 12 months when the remaining norbixin concentration was 4.42%.The findings showed that high concentrations are a protective factor against photo-degradation, and the shelf life of norbixin in aqueous formulation was 12 months at 30oC.