Context: The validation of a method is synonymous with the quality of the obtained results. The dissolution test is an analytical technique to evaluate the quality and stability of drugs during their development. Aims: To evaluate whether the UV spectrophotometric method for the quantification of losartan potassium in tablets from the dissolution test at pH 1.2, 4.5 and 6.8 meet with the validation parameters. Methods: The determination and evaluation of validation parameters were carried out under the guidelines of the regulatory entities. Linearity and range, accuracy, precision, specificity, limits of detection and quantification, robustness, stability of the sample solution were evaluated, and the filter test was added. All data obtained were subject to an analysis of variance and t-student analysis with a confidence level of 95% (α = 0.05). Results: The UV spectrophotometric method meets the acceptance criteria for each validation parameter. Likewise, it was identified that the prepared solutions were stable at pH 6.8 for 24 hours; however, they were not stable at pH 1.2 and 4.5. Conclusions: The method meets with the validation criteria and is suitable to be used for quantifying samples obtained from the losartan potassium tablet dissolution test.