A simple, precise, specific and accurate high performance thin layer chromatographic method has been developed for the simultaneous estimation of montelukast(MONT) and theophylline(THEO) in pharmaceutical dosage form. The separation was carried out on Merck HPTLC aluminum plates of silica gel G6O F254 (20 X 10 CM) with 250 μm thickness using Ethylacetate: Chloroform: Ethanol: Ammonia(6:4:3:1v/v/v/v) as mobile phase. HPTLC separation of the two drugs followed by densitometric measurement was carried out in the absorbance mode at 254 nm. The drugs were resolved satisfactorily with Rf values of 0.32 ± 0.01 and 0.52 ±0.01for MONT and THEO respectively. The linear regression analysis data for the calibration plots showed good linear relationship with R2 =0.9999 and 0.9999 for MONT and THEO respectively at the concentration range of 100-500ng/spot for MONT and 4000 to 8000ng/ spot for THEO. The method was validated for accuracy, precision, specificity and robustness. The limit of detection and quantitation were 131.01 and 597.82 ng/spot and 399.54 and 181.15ng/spot for MONT and THEO respectively. The proposed developed HPTLC method can be applied for identification and quantitative determination of MONT and THEO in bulk and drug formulation.