Abstract. In this study, a Regional Flood Frequency Analysis (RFFA) was applied to 33 stream gauging stations in the Eastern Black Sea Basin, Turkey. Homogeneity of the region was determined by discordancy (D i ) and heterogeneity measures (H i ) based on L-moments. Generalized extreme-value, lognormal, Pearson type III, and generalized logistic distributions were tted to the ood data of the homogeneous region. Based on the appropriate distribution for the region, ood quantiles were estimated for return periods of T = 5; 10; 25; 50; 100, and 500 years. A non-linear regression model was then developed to determine the relationship between ood discharges and meteorological and hydrological characteristics of the catchment. In order to compare regression analysis with other models, Arti cial Bee Colony algorithm (ABC) and Teaching-Learning Based Optimization (TLBO) models were developed. The equations were obtained using the ABC and TLBO algorithms to estimate ood discharges for di erent return periods. The analysis showed that the TLBO and ABC results were superior to the regression analysis. Error values indicated that the TLBO method yielded better results for the estimation of ood quantiles for di erent independent variables.