In this paper, a regional flood frequency analysis of Coruh Basin was performed with the L-moments method. Because the area of Coruh Basin is large (21100km(2)), and the climatic, hydrologic, and topographic characteristics vary throughout the basin, it was divided into four sub-regions for examination. Discordancy measure tests were performed for the sites located in each sub-region. The H heterogeneity test was carried out by performing 500 simulations with the Kappa probability distribution for the homogeneity of the region. With the help of a diagram of the L-moment ratios and by administering the Z goodness-of-fit measure test, the appropriate distribution was determined for each sub-region. The distributions were used to identify the quintiles according to various probabilities of non-exceedance. The accuracies of the estimated measured for the regional growth curves and quantiles were calculated using Monte Carlo simulation. Finally, the flow values determined from the quantiles estimated with the L-moments method were compared with those estimated previously with an at-site frequency analysis (Gumbel distribution) on the basin master plan for four large dams in the Coruh Basin.