Abstract: Estimation of the frequency of dominant discharge in the rivers is necessary for flood plain management. The determination of the dominant discharge is also very important for flood mitigation and estimation of flood damage. In this study the frequency of dominant discharge of the Kor River, upstream of Doroodzan Dam in the Fars Province is investigated and the rate of flow for dominant discharge was also determined. The flood discharge of 36 years at Chamriz station, upstream of the Doroodzan dam was collected and analyzed. The flood frequency analysis was used to find the ARI of the dominant discharge in the Kor River, upstream of Doroodzan Dam. It was found that the dominant discharge in the Kor River at Chamriz station has an ARI of 1.11 years on partial series analysis. The dominant discharge was found to be 552.75 m3 sec-1 for the Kor River, upstream of Doroodzan Dam.