These works were carried on to study the damage due to agricultural chemicals on silkworm and to find out the best ways to use them, considering, in the horticultural field, the utilization of them has rapidly been increased. The results may be summarized as follows: 1) The mulberry leaves being more than 100m from the horticultural field used the agricultural chemicals did not harm the silkworm. 2) Even if the mulberry leaves were located less than loom from the horticultural field sprayed with the chemicals, the silkworms were not injured after washing the mulberry leaves which were attached with the chemicals. 3) The chemicals, E.P.N., B. H. C. 2%, and Selesan were more seriously injured to silkworm than the other ones.