Three triazinyl reactive dyes containing the same chromophore but different Inactive systems were synthesized using trifluoro-s-triazine and trichloro-s-triazine as I L .live components. The rate of hydrolysis and the fastness properties of these triazinyl reactive dyes were studied and compared one another. The effect of pH on the hydrolysis rate of monofluorotriazinyl reactive dye was studied in various alkaline buffer solutions. It was found that monofluorotriazinyl reactive dye showed much higher hydrolysis rate than monochlorotriazinyl reactive dye, but little lower than dichlorotriazinyl reactive dye. The hydrolysis rate of monofluorotriazinyl reactive dye decreased as pH decreased in the alkaline region. Colour yields and fastness properties of dyeings were all within commercially acceptable limits.