Citrus fruit is one of the world’s most valuable fruit crops, and a major source of vitamin C to humandiet. As nonclimacteric, citrus fruit are harvested at their edible ripe stage. Navel orange (Citrus sinensis (L) Osbeck) varieties exhibit a similar phenology but diff erent harvest times. Some studies on the transcriptomics,proteomics and the metabolite profiling analysis of citrus fruit from late-ripening citrus mutants suggest the involvement ofseveral pathways that need further investigation regarding the intervarietal ripening time lag. This study aimsto establish the role for sucrose and citric acid pathways (main enzymes activity, transcript expression andproteomics), and their regulation (key-regulatory metabolites) in an early- and a mid-season navel orange variety,through fruit development, accounting for the unique citrus fruit morphology and the primarily unloading ofphotosynthates in the rind, which is then transported inwards across the various tissues to support fruit development andripening.