In the present investigation, the impact of salinity (by adding 100 mM NaCl to the nutrient solution as well as spraying with sodium nitroprusside, 10 μM SNP, NO source) on the fruit quality of tomato (Super strain B) plants grown under field conditions were studied. Irrigation with salinized nutrient solutions alone resulted in a significant suppression in the fruit fresh and dry biomass, length, diameter and volume as well as β-carotene and lycopene contents. This decrease was accompanied with a significant increase of Na accumulation, total alkaloids and antioxidants including total phenolics, flavonoids and ascorbic acid (ASA) contents. Similar to total phenolics and flavonoids, the content of some individual phenolic acids such as protocatechuic, vanillic, chlorogenic, ferulic and sinapic acids were of their high levels under saline conditions. Spraying the salinized plants with SNP improved the tomato fruit quality, to some extent, from salinity impact. Under the studied salinity level there was an enhancement in the synthesis of health-promoting compounds (phenolic compounds, flavonoids, ASA and alkaloids) in tomato fruits, with significant positive changes of other quality parameters.