Tomato fruit quality is a complex trait involving a number of components, including appearance, flavour, aroma and texture. There is a large range of genetic diversity in tomato for fruit quality components. Although a few major mutations may have a huge effect on fruit quality (notably the rin mutation), most of the components have a quantitative inheritance. Several Quantitative Trait Loci (QTL) mapping experiments have been performed, mostly on interspecific progeny. Many loci and QTL have thus been detected, revealing some QTL cluster regions. Tomato is a model plant for fruit development and composition, and knowledge about its physiology is rapidly increasing. This chapter examines the use of QTL to identify and determine favourable sensory characteristics, exploring current technologies and suggesting future trends for research in this area.