Galactomannan gum extracted from Cassia Saligna seeds was subjected to graft copolymerization using acrylic acid. Thegraft copolymerization has been performed using potassium persulphate as initiator.The rheological property of the grafted product and it is utilization as a thickening agent in printing cotton fabrics with reactive dyes was thoroughly investigated. The rheological properties and theviscosity at various rates of shear were investigated. Furthermore, the results obtained indicate that grafted product gum could be used safely as a thickener in printing of cotton fabric, using silk screen printing instead of the commercial thickener of sodium alginate.