In this work, improvement of wash and light fastness of basic, reactive and metal complex acid dyes applied to silk fiber by aftertreatment with syntan, syntan/metal salts and tannic acid/enzymes were investigated. The degummed and bleached silk samples were dyed with basic, reactive and metal complex acid dyes. Then, the dyed samples were aftertreated with syntan, syntan/metal salts and tannic acid/enzymes. Thus, all the dyed and aftertreated samples were washed according to ISO 105 CO6 wash test for silk fiber. However, the effect of a syntan aftertreatment in improving the fastness of basic, reactive and metal complex acid dyes to repeated washing at 50 0 C was enhanced by the sequential application of metal salts (MnSO 4 ,CuSO 4 ,K 2 Cr 2 O 7 ) and enzymes (protease and savinase). This was attributed to the formation of a large molecular size, low water-solubility complex situated at the surface of the dyed substrate which physically resists diffusion of dye from the dyed substrate during washing. The effect of above aftertreatments on light fastness, samples of dyed and aftertreated silk were tested according to ISO 105 BO2 light fastness test. This was observed that aftertreatments had no effect on light fastness of metal complex acid dyes, but the light fastness of the basic dyeings reduced by aftertreatments. In this work, improvement of wash and light fastness of basic, reactive and metal complex acid dyes applied to silk fiber by aftertreatment with syntan, syntan/metal salts and tannic acid/enzymes were investigated. The degummed and bleached silk samples were dyed with basic, reactive and metal complex acid dyes. Then, the dyed samples were aftertreated with syntan, syntan/metal salts and tannic acid/enzymes. Thus, all the dyed and aftertreated samples were washed according to ISO 105 CO6 wash test for silk fiber. However, the effect of a syntan aftertreatment in improving the fastness of basic, reactive and metal complex acid dyes to repeated washing at 50 0 C was enhanced by the sequential application of metal salts (MnSO 4 ,CuSO 4 ,K 2 Cr 2 O 7 ) and enzymes (protease and savinase). This was attributed to the formation of a large molecular size, low water-solubility complex situated at the surface of the dyed substrate which physically resists diffusion of dye from the dyed substrate during washing. The effect of above aftertreatments on light fastness, samples of dyed and aftertreated silk were tested according to ISO 105 BO2 light fastness test. This was observed that aftertreatments had no effect on light fastness of metal complex acid dyes, but the light fastness of the basic dyeings reduced by aftertreatments