Vegetables especially leafy ones are the major source of nitrate and nitrite in human diet. Because
of the potential health hazards result in high intake of nitrate and nitrite, determination of these ions content
in vegetables the concentration has been considered and measured in many countries. The aim of this research
was to determine the concentration of nitrate and nitrite in leek and spinach sampled from three central cities
of Mazandaran state (IRAN). So, 12 samples of each vegetable have been gathered from farmlands of 4
geographical regions in each city. At last, we assessed 36 leek samples and 36 spinach samples. The
measurement was based on ISO Method (NO.6635). Data has been analyzed with T-test and ANOVA.According
to the results, the average of nitrate and nitrite content in all of the samples was less than standard limits.
Qaemshahr-sampled leek had significantly higher nitrate content than 2 other cities (P<0.01), on the other hand,
spinach sampled from Sari had significantly lower nitrate content than 2 other cities (p< 0.05).