This research was done to verify the impact of manure spreading on the runoff when a rain occurs after the manure has been applied to the soil. As the size of swine production units increase, manure has often to be applied late in the fall or early in the spring regardless of the climatic conditions which could lead to runoff. As the experiments were done in laboratory, the results have to be considered with caution. The real values obtained may not be applicable for fields situations however the general behavior is likely to be the same. When manure is applied, the runoff situation will happen sooner as the soil is already humid by the important volume of liquid applied, the volume of runoff is also increased and the infiltration rate is lower particularly if the rain occur 1 hour after spreading.