In soil incubation experiments we examined if there are differences in the kinetic parameters of atmospheric methane (CH 4 ) oxidation in soils of upland forests and forested peatlands. All soils showed net uptake of atmospheric CH 4 . One of the upland forests included also managed (clear-cut with or without previous liming or N-fertilization) study plots. The CH 4 oxidation in the forested peat soil had a higher K m (510 μl l - 1 ) and V m a x (6.2nmol CH 4 cm - 3 h - 1 ) than the upland forest soils (K m from 5 to 18 μl l - 1 and V m a x from 0.15 to 1.7nmol CH 4 cm - 3 h - 1 ). The forest managements did not affect the K m -values. At atmospheric CH 4 concentration, the upland forest soils had a higher CH 4 oxidation activity than the forested peat soil; at high CH 4 concentrations the reverse was true. Most of the soils oxidised CH 4 in the studied pH range from 3 to 7.5. The pH optimum for CH 4 oxidation varied from 4 to 7.5. Some of the soils had a pH optimum for CH 4 oxidation that was above their natural pH. The CH 4 oxidation in the upland forest soils and in the peat soil did not differ in their sensitivities to (NH 4 ) 2 SO 4 or K 2 SO 4 (used as a non-ammonium salt control). Inhibition of CH 4 oxidation by (NH 4 ) 2 SO 4 resulted mainly from a general salt effect (osmotic stress) though NH 4 + did have some additional inhibitory properties. Both salts were better inhibitors of CH 4 oxidation than respiration. The differences in the CH 4 oxidation kinetics in the forested peat soil and in the upland forest soils reveal that there are differences in the physiologies of the CH 4 oxidisers in these soils.