We cloned the gene of d-limonene synthase (ArLMS) from Agastache rugosa (Labiatae). The function of ArLMS was elucidated by the preparation of recombinant protein and subsequent enzyme assay. ArLMS consisted of 2077 nucleotides including 1839 bp of coding sequence that encodes a protein of 613 amino acids. This protein has a 60 kDa molecular weight, which is identical to that of d-limonene synthase from Schizonepeta tenuifolia (Labiatae). The deduced amino acid sequence of ArLMS shows high homology with the known d- and l-limonene synthases from Labiatae plants. Here, we discussed the amino acid residues responsible for the stereochemical regulation in limonene biosynthesis.