Effects of sampling time, storage period, and three different methods of storage on dehydrogenase activity of the topsoil of Phaeozem and three Orthic Luvisols were studied. Analysis of seasonal variability showed statistically significant differences in the dehydrogenase activity between four seasons of the year in the Orthic Luvisol developed from silt. Differentiation among the activity of the soil samples taken in different seasons of the year is maintained for the 7 years of storage. The highest dehydrogenase activity of fresh soils was found in the Phaeozem where it was about four times higher than in the Orthic Luvisol developed from silt. That tendency was preserved in all the experiments irrespective the storage time and methods. Air-drying resulted in a considerable decrease of dehydrogenase activity after sample storage for a period from one to two months with a tendency to increase an increasing storage period exceeding about 20 months. The subsequent preincubation of the air-dried soil samples at room temperature showed a more stabile dehydrogenase activity than in the case of other methods of storage. The results suggest that the worst method of storage for the investigated soils is storage at 4 oC for the time longer than 1 month. The investigations demonstrated that the main factor affecting the levels of dehydrogenase activity is sampling time. It seems that dehydrogenase activity is affected by the environmental properties in the field so strongly that it “keeps” its activity for a long time.