HPTLC-densitometry method was developed and validated for simultaneous determination ofrnantiretroviral drugs tenofovir disoproxil fumarate and lamivudine in fixed dose combi nations.rnThe method was based on HPTLC separation of the two drugs followed by densitometricrnmeasurements of their spots at 257 nm. Toluene-methanol (6:4, v/v) was used as mobile phasernand HPTLC aluminum sheets of si lica gel 60 F254 as stationary phase and detection of the spotsrnwere made by observation under short wavelength (254 nm) UV li ght. The system was foundrnto give compact spot for lamivudine (Rr= 0.32 ± 0.02) and tenofovir disoproxil fumarate (Rr =rn0.57 ± 0.02). The method was validated for precision, accuracy and robustness. The linearrnregression analysis data for the calibration plots showed good linear relationship with r2 =rn0.998 in the concentration range 100-900 ng/spot for tenofovir disoproxil fumarate and linearrnrelationship with r2 = 0.994 in the concentration range 200-800 ng/spot for lamivudine. Thernmean value of determination coefficient, slope and intercept were 0.998 ± 0.0012 and 0.994 ±rn0.002, 4.80 ± 0.076 and 8. 12 ± 0.21 , 232.80 ± 36.21 and 478.16 ± 72.85 for tenofovirrndisoproxil fumarate and lamivudine, respectively. The intra-day and inter-day precision wasrnless than 3% relative standard deviation (RSO