Leaf spot diseases were found on safflower (Carthamus thinctorius) leaf in several fields located in Euisong- Gun, Gyengbuk province in Korea. The infected leaf rate of the diseases in surveyed area were different each years from 2001 to 2003 such as about 5%, 10%, and 30%, repectively. The typical symptoms of diseases appeared first as small, light brown spots on leaves. And then spot turn dark brown and magnified. And yellow decoloration zone appeared surrounding dark brown spots. Mycological characteristics of Alternaria carthami, isolated from safflower mature leaf spot were dark gray colonies, conidiophores simple erect, septated, 40~80 μm length; conidia solitary, straight, body size of without beak length 40~100 μm, 10~15 μm thick, Number of transverse septa 4~10 and longitudinal septa 4~7; beak with 2~4 septa, 30~65 μm lenght. And A. alternata, isolated from old leaf were gray~dark gray colonies, conidiophores simple or branched, 20~110 μm length; conidia long chaines, short conical or cylindrical beak, 2~6 transverse septa and several longitudinal septa, body size of without beak length 30~60 μm, 10~20 μm thick ; beak length 5~35 μm. These are the first report on the leaf spot of safflower caused by Alternaria carthami, A alternata in Korea.