The gene encoding nitrate reductase was cloned from the DNA isolated from cultured spinach (Spinacia oleracea cv. Hoyo) cells and sequenced. The clone contains 7612 nucleotides of the gene which consists of four exons interrupted by three introns. The transcription start site was determined by primer extension analysis and located 193 bp upstream of the ATG translation initiation codon. The 5'-flanking region contains a TATA box and CAAT box.