The study area is the ​​N'zo-Sassandra (West of Ivory Coast) watershed which is located between longitudes 7°15' and 8°05' West and latitudes 6°50' and 7°50' North. Its area is estimated at 4,310 km2. The objective of this study is to analyze the forecast of the flood flows of the N’zo (Sassandra) river located in the west of the Ivory Coast. The hydroclimatic data used (rainfall, ETP, flow) within the framework of this study extend on the one hand over the historical period (1961-2017) and on the other hand over the future period (2036-2065). The methodological approach adopted is based respectively on the analysis of past floods, the evaluation of the chosen rainfall-discharge model, the prospective climatic analysis and the prospective analysis of the flood flows. The variables used to describe the future evolution of these floods are the decennial and centennial quantiles of the annual maximum monthly mean discharges. Thus, an optimistic climate forecast scenario was used (RCP 2.6). This climatic scenario then fed into a hydrological rainfall-discharge model (GR2M model) calibrated to the reference period 1961-1990 and validated over the period 1991-2017. In response to climate forcing, future monthly flood discharges (QMXA) were simulated. The main results show that the best statistical law retained following the frequency analysis of the flood flows is the Gamma law which was used to estimate the frequency flows. The GR2M model evaluated, presented a good performance in calibration (79.7%) as in validation (82.7%) and demonstrated a great robustness (+3%) therefore a great capacity to reconstitute the flows of N'zo in Kahin. The climate forecast has shown a decrease in precipitation (-19.7%) and an increase in temperature (+1.6 °C) in the middle of the current century (2036-2065). The expected flood flow quantiles in the middle of the 21st century (2035-2065) are respectively 168.85 m3/s for the ten-year flow and 299.58 m3/s for the one-year flow. Thus, in response to climate change, the forecast of flood flows leads to a worrying drop in frequency flood flows, respectively of the order of 64.56% for the ten-year flood and 61.73% for the 100-year flood compared to their current values.