We found nine novel polymorphisms in the upstream region of the human dopamine D4 receptor (DRD4) gene of Japanese by direct sequencing. These polymorphisms are -809G > A, -768G > A, -616C > G, -603T > del, -602G > del, -600G > C, -376C > T, -291C > T, and -128G > T. One known polymorphism, -521C > T, was also recognized. Six of these sites were identified as restriction fragment length polymorphisms (RFLPs).