Accurate estimating of daily streamflow forecasting is one of the prominent topics in water resources activities. In this paper, an integrated method including decomposition technique based on the ensemble empirical mode decomposition (EEMD) combined with multivariate adaptive regression spline (MARS) was carried out to predict daily streamflow values. Daily streamflow value datasets collected from two stations in Iran (Gachsar and Kordkheyl) were selected. After dividing into calibration and validation datasets, each of them was decomposed by EEMD. Crow search algorithm (CSA) was used to optimize the MARS parameters (MARS-CSA). The performance of the integrated model (EEMD-MARS-CSA) was investigated by error indices (correlation coefficient (R), root mean squared error (RMSE), mean absolute error (MAE), Nash–Sutcliffe efficiency (NSE), as well as RMSE to standard deviation ratio (RSR)). From the results, EEMD was an important tool for increasing model accuracy and EEMD-MARS-CSA outperformed other alternative methods for daily streamflow estimation. According to one-day-ahead flow forecasting, EEMD-MARS-CSA (R = 0.94, RMSE = 5.94 m3/s (Kordkheyl) and R = 0.98, RMSE = 0.71 m3/s (Gachsar)) outperformed EEMD-MT/MARS, MT, and MARS models. Furthermore, RSR criterion of EEMD-MARS-CSA was reduced by 18%, 16%, and 17% for 3-days, 1-week, and 2-weeks-ahead streamflow forecasting compared to MARS-CSA model, respectively, for Gachsar station.