Heavy metal accumulation in vegetable tissues often poses a great risk for human health. In the present study, accumulation of heavy metal in green leafy vegetable crops of coriander, garden cress, lettuce and spinach were evaluated under waste water irrigation in fields located in Kahrizak, on the southern edge of the metropolitan city of Tehran, Iran. Atomic absorption spectrophotometery was used for determination of heavy metal concentrations in leaf tissue. The results showed that heavy metal concentrations in soil and irrigation water were significantly high than allowable levels. Analysis of plant leaf tissue showed that spinach and garden cress accumulated higher concentrations of heavy metals compared to coriander and lettuce plants. Central leaves of lettuce showed the lowest heavy metal concentration compared to outer leaves or leaves of other vegetable crops, and can be the safer product for fresh consumption. The results indicate that the vegetables produced in the region are not suitable for fresh consumption and the agricultural activities should change towards ornamental or industrial crops production.