The method for the determination of Valaciclovir HCl active substance in film coated tablets has been developed and validated. The study describes simple, precise and accurate HPLC analytical procedure and validation of the method which is successfully applied for analysis of tablet samples. The components are separated on ACE 250 x 4 mm column with a mobile phase obtained by mixing 850 ml of distilled water, 150 ml of methanol and 0.5 ml of HCl, at pH 2.1, pumped at 1 ml/min with UV detection at 254 nm. The results obtained showed a high reproducibility in retention time value with the R.S.D. of 0.90%. The other considered validation characteristics of methods where precision, accuracy and linearity. The precision of the method was determined by measuring the series of 6 homogenous authentic samples under prescribed conditions. R.S.D value obtained was 0.82%. The accuracy of the method was evaluated using data points from the standard curves by comparison of the expected values and amounts calculated by linear regression which was R.S.D = 0.58%. Linearity of the method was determined by calculation of the regression line using the least squares analysis and by investigating the accuracy of the assayed method. Determination coefficient value was r2 = 0.9996%.