Acetone and xylene can be easily found in clean rooms during various cleaning processes. A recently developed experimental setup was applied to study humidity and temperature dependences of adsorption and desorption rates of acetone and xylene on silicon wafers. The humidity dependence is somewhat stronger for acetone compared with xylene at ambient temperature, which can be attributed to the physical-chemical properties of both compounds. Adsorption and desorption rate constants of acetone and xylene are temperature dependent in the range of 273-333 and 273-343 K, respectively. The temperature dependence of the Langmuir constant (K) for acetone is given by K(T)=1.80x10(-3) exp(615.90/T) at a gas-phase concentration of c(g)=1450 mu g C m(-3) at relative humidity (RH)=0%, and that for xylene is given by K(T)=2.57x10(-4) exp(1065.80/T) at a gas-phase concentration of c(g)=1250 mu g C m(-3) at RH=0%. From this data set, the adsorption enthalpies Delta H-ads=-(5.1 +/- 0.02) kJ mol(-1) and Delta H-ads=-(8.9 +/- 0.01) kJ mol(-1) were obtained for acetone and xylene, respectively.