Effects of metribuzin on the activity of some enzymes in soil was investigated. Trials were set up in the laboratory on a clay loam soil. Metribuzin was applied at 12.0, 24.0 and 60.0 mg/kg soil rates and soil samples were collected 3, 7, 15, 30 and 45 days after metribuzin treatment for analyses. Alkaline phosphatase, acid phosphatase, dehydrogenase, urease and ?-glucosidase were recorded. The results showed that the intensity of metribuzin effects on the activity of enzymes depended on treatment rate, exposure time and enzyme group. Metribuzin had an inhibiting effect on acid phosphatese and dehydrogenase, as well as on alkaline phosphatase in the initial stage before it turned into a stimulating one, while metribuzin stimulated urease and had no effect on ?-glucosidase.