The stratification and movement of moisture in the forest floor were examined in both the field and the laboratory. Experimental results from forest duffs studied in California and Ontario show that after rain the highest moisture content in the forest floor is not at the duff-mineral soil interface but somewhat above it. Results indicate that this 'inversion' is caused neither by a lack of water reaching this interface nor by the inability of the lowest duff layer to absorb water. With increasing time after rain, the highest moisture content was found to be at a lower level in the duff layer until eventually it existed at the duff-mineral soil interface. Evaporation from the surface of the forest floor is the most important factor to be considered in determining this characteristic duff-drying pattern. The actual downward movement of moisture makes a negligible contribution to the pattern.