The results of studying the effect of pendimethalin and its mixtures on the emergence of Portulaca oleracea weed revealed that in general, the least effective treatments were pendimethalin mixture with capl oil with5.73weeds/m² as a mean followed by pendimethalin alone 9.75. While the most effective treatments resulting in low mean were pendimethalin  + phosphoric acid 1.92, followed by the other treatments. For Xanthium brasilicum the mean values showed that pendimethalin half dose with phosphoric acid and with palm oil was the most effective mixture with 1.33 and 1.58 weed/m². The mixture with citric acid was the least effective at 6.02 weeds/m² beside pendimethalin alone with 7.33 weeds/m². While the full dose of pendimethalin was more effective in inhibiting the emergence of both tested weeds. Pendimethalin mixture with phosphoric acid was the most effective mixture in suppressing both weeds' emergence. In general, the fresh weight obtained from treatment with half recommended dose was higher than that obtained on treatment with the full dose. Pendimethalin alone and its mixture with citric acid resulted in fresh weight higher than all the other treatments for the full dose and half of the two tested weeds. There was a very high % germination of the cucumber as a test plant in the treated soil layer 5-10 cm. The persistence of pendimethalin with Arabic gum was higher than all the other treatments. The highest RL₅₀ value was that of pendimethalin with Arabic gum at 45.31days, while the lowest was that of pendimethalin with palm oil at 31.80 days