This work presents the results obtained in using olive mill wastewater (OMW) as sacrificial agent for the photocatalytic H-2 evolution from water, at ambient temperature and pressure. The effects of irradiation time, catalyst amount, pH, and OMV/concentration have been investigated. Under the best experimental conditions (4 h UV-A irradiation, 2 g L-1 Pt/TiO2, OMW 3.3% v/v, COD 944 mg L-1, pH 3) up to 44 mu mol H-2 were generated from aqueous samples. Consecutive irradiation cycles (4 x 4 h) on the same sample provided ca. 280 mu mol H-2, corresponding to 82% of the yield observed, under the same conditions and COD value, by using glucose as test sacrificial agent. H-2 evolution was strongly improved (+81%) by pre-treating OMW with magnesium silicate (125 g L-1, 6 h contact), achieving a production of ca. 80 mu mol H-2 by 4 h UV-A irradiation. The possibility to exploit sunlight in the photocatalytic process was gained by using Eosin Y/Pt/TiO2. Under solar light the H-2 yield resulted to be 66% with respect to that obtained by UV-A radiation. Beside some general mechanistic aspects of the photocatalytic process, benefits and drawbacks in recycling OMW for photocatalytic H-2 evolution from water have been highlighted. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.