Sodium salt of partially carboxymethylated guar gum [Na-PCMGG] of different degrees of substitution (DS) were synthesized by heterogeneous and homogeneous solution methods. The DS was measured by Amberlite IRA 96 anion exchange resin. The reaction parameters viz. reaction time, reaction temperature, effect of NaOH, effect of mono chloro acetic acid was optimized. Na-PCMGG having optimized reaction condition was characterized by Fourier transforms infrared spectroscopy (FTIR).