A fast and simple HPLC-PDA method for rosmarinic acid quantification in Rosemary leaves powder was validated. The analyses were performed using a C18 column in isocratic conditions and detection at 254 nm. Performing the system suitability tests, the method showed to be capable of providing data of acceptable quality. Results showed that the method was selective, linear for concentration ranges between 2.5-50 μg.mL–1 , sensitive, precise, accurate and robust. The main advantages of the method were the simplicity and promptness of sample analysis, as well as equipment convenience. These results allowed us to conclude that it can be successfully applied on the routinely quality control of Rosemary phytopharmaceuticals inputs.