Enzyme activities (β‐glucosidase, N‐acetylglucosaminidase, phosphatase, and arylsulfatase) were determined in various wetland soils. Soil samples from 21 locations were analyzed, covering a latitudinal range of 5° to 60° N and four types of wetlands (bog, fen, marsh, and swamp). Overall, the greatest activity was found in swamps, followed by marshes. Bogs and fens exhibited less activity than the other two types of wetlands. It appeared that cool temperature and low quality of litter were the main reasons for such low activity. Mean enzyme activity determined in this study was compared to decomposition rates of leaf litter in the literature. Percentage of mass loss of litter in the first year was highly correlated with mean enzyme activity when we compared values by wetland types. This result suggests that enzymatic analysis can be used as an index for litter decomposition rates in wetlands at a worldwide scale.