Tomato shelf-life is important for its fresh market usage especially for exporting and transporting tomato in tropicalclimate. To increase the shelf-life, delaying maturity is one of the powerful methods. A ripening gene related to the fruit maturitydelaying was previously known through tomato mutation. RIPENING-INHIBITOR (Rin) from the recessive mutation effectivelyblocks the ripening process, and when the hybrid (Rin/rin) was formed it shows slow-ripening and long shelf-life. Since breedersneed the long shelf-life character in the tomato breeding program, we had set out a series of experiments to develop a Rin relatedDNA marker. We searched for the proper primer sequences in the deletion region between Rin and rin mRNA sequences, andalso in the intron region of rin. Primers that simultaneously amplified two bands with a co-dominant pattern were selected andconverted to the Sequence Characterized Amplified Region (SCAR) marker. As a preliminary data, the SCAR marker clearlydistinguished genotypes between heterozygote (Rin/rin) and homozygote (Rin/Rin, rin/rin), and this would help select the tomatolines that have a characteristic of long shelf-life.