Abstract: Chlorophyll-a (chl-a) concentration values obtained from in situ measurements and remote sensing data are compared. Ocean color data was provided by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite. The global empirical algorithms OC2v4 and OC4v4 were used to estimate the chl-a concentration from the detected radiance values in multiple wavelengths. In situ data includes spectroradiometer radiance measurements and measurements of a profiling natural fluorometer (PNF) collected during a oceanographic cruise in the Brazilian Southeast coast in May 2003. The chl-a concentration, estimated from radiances, are checked against the concentration determined from laboratory chl-a fluorometric analysis. These analysis were carried out from the ocean water also collected during the cruise. The comparison of in situ and remote sensing data was difficult due to the poor number of match-up's. Concomitant satellite data and in situ data were available for only three stations. However, some trends can be observed: (i) there is a good correlation between satellite and spectroradiometer data for chl-a concentration values, (ii) high chl-a concentrations are underestimated by the satellite, but overestimated by the spectroradiometer, (iii) low chl-a concentrations are overestimated by both. It can be concluded that ocean color algorithms should be improved in order to yield a better accuracy for remote sensing chl-a estimations. A closer investigation of this region is required concerning the development and use of a regional algorithm for deriving ocean color chl-a concentration.