Laboratory studies on degradation of MCPA were performed in different soil horizons of three Polish agricultural soils. Hyperdystric Arenosol (Ap, BwC, C), Haplic Luvisol (Ap, E, Bt) and Hypereutric Cambisol (Ap, Bw, BwC) were selected for investigations as representative of Polish agricultural soils. Degradation experiments were performed at 5 and 25°C. Fitting the data to the exponential form of the three-half kinetic model gave good results, worse in the case of a first-order kinetic equation due to the lag-phase observed. Therefore the zero-order kinetic equation was also used. The values of DT50 at 25°C for Ap horizons of soils were in the range of 1.5-6.9 days, for BwC, E and Bw horizons 8.7-20.1 days, and for C, Bt and BwC 27.6- 85.8 days. The activation energies for all horizons of all soils were in the range of 47.8-67.8 kJ mol^-1. The results showed significant correlations between the zero- and first-order rate coefficients for MCPA degradation and the contents of microbial biomass carbon, activity of the enzyme dehydrogenase and fluorescein diacetate hydrolyse in the studied soils.