The attenuation of global sun radiation in seven-year-old coffee trees (Coffea arabica, L. var Bourbon), grown under shade was studied. Extinction coefficients obtained varied between 1,05 and 2,03, being higher at 13:00 hour (local time). The solar attenuation was fitted exactly to the Weibull model. The higher attenuation of solar radiation was made at the third up level of the canopy where the 30% percent of the leaf area are con fined.