This work is concerned with the simultaneous determination of diclofenac potassium and metaxalone in a bulk drug and pharmaceutical formulation by high performance thin layer chtromagraphic method (HPTLC). The precoated silica gel 60 F254 aluminum plate was selected as the stationary phase and solvent system consisted of chloroform: methanol (8:1 v/v) used as developing solvents. The detection of diclofenac potassium and metaxalone was carried out at 281 nm. The developed method was validated for linearity, accuracy, precision, limit of detection, limit of quantitation and robustness parameters. The correlation coefficient of diclofenac potassium and metaxalone were 0.996 and 0.998 observed respectively. The average percentage recovery of diclofenac potassium and metaxalone were found to be 99.39 % and 99.85 % respectively. Intra and inter day precision measured as coefficient of variation were less than 2% for both analytes.The proposed HPTLC method has potential applications for determination of diclofenac potassium and metaxalone in combined tablet dosage form.