Compositional characterization was performed on seven 'Pomodorino del Piennolo del Vesuvio' (PPV) tomato landraces, a signature product of Campania (Italy) threatened by genetic erosion. Characterization encompassed determinations of macro-minerals, soluble carbohydrates, starch, acidity, lycopene, polyphenols, anthocyanins, protein and free amino acids. Exceptionally high dry matter (13.0 ± 0.2%) and sugar content (101.3 ± 3.8 μmol g fw) and very low (0.007-0.009) Na/K ratio were invariably obtained across landraces, contrasted by significant variation in acidity (28.5-3.9 g kg dw). Giagiù, Acampora and Riccia San Vito differentiated by high polyphenols content (131.8 ± 2.5 mg 100 g) while Acampora, Cozzolino and Fofò by high lycopene content (13.3 ± 10.6 mg 100 g fw). Glutamate, GABA and glutamine represented 65% of the 22 detected amino acids mean total content. Glutamate, linked to umami taste, was highest (19.2 µmol g fw) in Fofò. Our results will contribute towards the systematic documentation of sensory and functional quality profiles of an important collection of tomato landraces.