Aim of the work was to develop and validate a method for determining the quantitative content of amoxicillin in suspensions for injections by the method of liquid chromatography. Materials and Methods: The analysis was performed on a Dionex Ultimate 3000 liquid chromatograph, equipped with an LPG-3400SD pump, an ACC-3000 autosampler, and a DAD-3000 diode array detector. The samples were separated on an Acclaim C18 250 × 3.0 mm chromatographic column. The mobile phase was a mixture of 0.01 M potassium dihydrogen phosphate with a pH of 2.5 and acetonitrile in a volume ratio of 4:1. The eluent supply rate was 0.5 ml/min, amoxicillin was detected at an absorption wavelength of 225 nm. The test and standard samples were dissolved in the mobile phase to a concentration of 150 μg/ml of amoxicillin. The results were calculated using the Chromeleon 7.2 software. We determined the overall uncertainty of the analysis, the parameters of the chromatographic peak, and validated the method according to the indicators of accuracy, precision, linearity, robustness (stability of solutions over time). Results: Under the above conditions, it was possible to completely separate amoxicillin and other components of the studied medicines. It was found that amoxicillin was stable in the test solution for 4 hours, and the suitability parameters of the chromatographic peaks did not exceed the limits specified in the recommendations for analytical research methods. The calibration curve was linear in the recommended range (80–120% of the nominal concentration of the active substance). The coefficient of linearity (R2) was 0.9997. The extraction of amoxicillin under the conditions of its addition to the matrix and the repeatability of the method were within the limits established by the State Pharmacopoeia of Ukraine. Conclusion: The method is suitable for routine use in the study of the quantitative content of amoxicillin in suspensions for injections.