Ribosomal protein complex with ribosomal RNA to form the subunits of the ribosome serve essential functions in protein synthesis. A full-length cDNA (PRPS4) encoding ribosomal protein S4 has been isolated and its nucleotide sequence determined in ginseng plant (Panax ginseng). A PRPS4 cDNA is 1105 nucleotides long and has an open reading frame of 792 bp with a deduced amino acid sequence of 264 residues (pI 10.67). The deduced amino acid sequence of PRPS4 matched to the previously reported ribosomal protein S4 genes. Their degree of amino acid identity ranged from 68 to 92%. Phylogenetic analysis based on the amino acid residues showed that the PRPS4 grouped with ribosomal protein S4 of S. tuberosum (CAA54095).