The dye permeability of the chlorinated wool has been discussed in connect with dye constitution and water absorbency. The chlorinated wool tends to increase the water absorbency and the degree of swelling, which affect to the dye permeability. The mixture of equal parts of chlorinated wool and normal wool were dyed with simple acid dyes which differ in the number of sulphonic acid groups. It is confirmed that the ratio of dye take up by normal wool and chlorinated wool increases with increasing sulphonated groups of dye and the rate of dyeing decreases with increasing basicity of simple acid dye as elucidated by Townend and Simpson for dry-chlorinated wool.