Organic solid wastes are the most abundant sources for biohydrogen production. Dry fermentation system has many advantages over continuously fed reactor systems for treatment of organic solid wastes. In this study the effect of percolation frequency on yield of biohydrogen production from fruit and vegetable wastes using dry fermentation system was examined. For this purpose 2 times percolation per day, 1 time percolation per day and 1 time percolation per 2 days frequency were compared and the hydrogen yields were observed as; 57 mL H-2/gVS(removed), 53 mL H-2/gVS(rernoved) and 68 mL H-2/gVS(rernoved) respectively. The percolation frequency didn't affect the overall yield but significantly affected the biohydrogen producing reactor of the dry fermentation system. 80% of the hydrogen was produced in percolation tank during 1 time per 2 days feeding and almost all hydrogen production was conducted in dry fermenter during 2 times per day percolation. Therefore the percolation frequency is found to be very important for system operation characteristics. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.