Print pastes contain thickeners ''thickening agents'' that are often natural or synthetic polymers. The role of thickeners is thickening of print paste and making it more viscous to avoid lateral diffusion and improve finesse of motifs. The aim of this paper is to study the effect of type and concentration of thickeners in print paste (using vat dyes and Two-stage method) on fastness properties and color yield. Thickeners used usually, in this method, are sodium alginate, guar gum and starch ether. Conventional print paste recipe applied in this method give low fastness to dry and wet rubbing when we print in dark shade. We used only two thickeners in various concentrations, and then the fastness to rubbing is evaluated. The viscosity of print pastes is measured because of its effect on the penetration of the print paste across the fabric, thus its effect on color yield.