The objective of this work was to evaluate the efficiency of the photocatalytic process in the vinasse treatment using solar radiation. The degradation tests were carried out during 5 days consecutive with solar irradiation from 8:00 a.m. to 17:00 p.m. TiO2, Nb2O5-TiO2 and immobilized TiO2 in glass beads (TiO2/beads) were used as photocatalysts. The characterization results showed that the catalysts presented distinct textural, structural and morphologic properties, conferring distinct photocatalytic behavior to them. The degradation results showed that photolysis was not efficient in the vinasse mineralization and that Nb2O5-TiO2 was the most photoactive material. TiO2/beads presented activity higher than the suspended TiO2, indicating a positive interaction between TiO2 and glass beads. The vinasse toxicity was evaluated using bioassays with Artemia saline and it verified significant reduction in the vinasse toxicity after photocatalytic treatment, mainly with Nb2O5-TiO2 and TiO2/beads. Evidencing that photocatalysis under sunlight was efficient in the vinasse treatment and that the Nb2O5-TiO2 is an excellent option as photocatalyst. (C) 2007 Elsevier B.V. All rights reserved.