In this study, zinc oxide nano-particles, known to have photocatalytic and high UV protection properties, were used in the finishing process to prevent chromium(VI) formation as a result of photoageing in the garment leather products. The researches were carried out on the chrome-tanned garment leather. Nano zinc oxide at the proportions of 0.25%, 0.5% and 1% on nitrocellulose (N/C) emulsion amount were used in the finishing process of leathers. The finished garment leathers were exposed to an artificially accelerated ageing process at 80 degrees C for 24 hours and 80 degrees C/UV for 24 hours. Cr(VI) amounts in each leather sample were evaluated in compliance with ISO/FDIS 17075 standard test method based on the reaction of chromium(VI) with diphenylcarbazide and subsequent colorimetric determination at 540nm by using a double beam Shimadzu 1601 UV visible region spectrophotometer. The leathers finished using nano ZnO were compared to control samples and the way in which ZnO nanoparticles affect Cr(VI) formation was statistically examined by the analysis of variance (ANOVA) and Duncan test. According to research results, it was determined that Cr(VI) amounts arising in the garment leathers after photoageing were rather high and that the use of nano zinc oxide in finishing process substantially eliminated Cr(VI) formation statistically by providing high UV protection. 18.31 +/- 2.46ppm of Cr(VI) occured under 80 degrees C/UV for 24 hours was decreased to less than 3ppm by 1% of nano ZnO. Using 0.25% and 0.5% of nano ZnO on the amount of N/C emulsion applied also reduced the levels of Cr(VI) to under 3ppm.