A HPLC method with DAD detection for determination of melatonin in Lamium album flos was developed. The analysis was carried out on RP18 column using mixture of methanol and water (28:72 v/v) as a mobile phase. Established calibration curve (r>0.9994), precision (RDS values ranged from 0.5% to 1.5%), detection limit (0.025 μg/mL) and quantification limit (0.076 μg/mL) were found to be satisfactory for the proposed method. The determined content of melatonin in Lamium album flos was 0.15 μg/g of dry plant material. Key words: melatonin, HPLC, Lamium album flos