Tomato (Solanum lycopersicum) is a vegetable of great economic importance and its use is largely determined by the shape and size of the produce. While five major fruit weight genes controlling fruit size FW2.2 (CNR), FW3.2 (KLUH), FW11.3 (CSR), locule number LC (WUS), and FAS (CLV3) have been cloned, breeders would greatly benefit from new genes controlling fruit size. Two related experiments were conducted to characterize an underused germplasm and to identify new QTL controlling fruit size. Genotyping and phenotyping of 167 accessions collected from the center of origin of tomato revealed a large variation in fruit size that was not explained by the known genes. This knowledge led to the creation of F2 mapping populations for Bulk Segregant Analysis with QTLseq, and the identification and confirmation of a novel fruit weight QTL at the bottom of chromosome 2. Future efforts will be aimed to clone the underlying gene.