Yellow or transparent fruit peel color is caused by the accumulation or lack of naringenin chalcone (NG, C) in fruit peel and determines the red or pink appearance of tomato fruit, respectively. NGC biosynthesis is regulated by the SlMYB12 gene of the Y locus on chromosome 1, and DNA markers derived from SlMYB12 would be useful for marker-assisted selection (MAS) of tomato fruit color. To develop a gene-based marker, 4.9 kb of the SlMYB12 gene including a potential promoter region was sequenced from the red-fruited (YY) line 'FCR' and pink-fruited (yy) line 'FCP'. Sequence alignment of these SlMYB12 alleles revealed no sequence variations between 'FCR' and 'FCP'. To identify SlMYB12-linked single nucleotide polymorphisms (SNPs), 'FCR' and 'FCP' were genotyped using a SolCAP Tomato SNP array and CAPS markers (CAPS-456, 531, 13762, and 38123) were developed from the four SNPs (solcap_snp_sl_456, 531, 13762, and 38123) most closely flanking the SlMYB12. These CAPS markers were mapped using F2 plants derived from 'FCR' × 'FCP'. The map positions of the fruit peel color locus (Y) were CAPS-13762 (0 cM) -456 (11.09 cM) -Y (15.71 cM) -38123 (17.82 cM) -531 (30.86 cM), and the DNA sequence of SlMYB12 was physically anchored in the middle of CAPS-456 and CAPS-38123, indicating that fruit peel color in domesticated tomato is controlled by SlMYB12. A total of 64 SolCAP tomato germplasms were evaluated for their fruit peel color and SNPs located between solcap_snp_sl_456 and 38123. Seven SNPs that were detected in this interval were highly conserved for pink-fruited accessions and specific to transparent fruit peel traits, as depicted by a phenetic tree of 64 accessions based on the seven SNPs.