Hydrochlorothiazide (HCT) is a diuretic drug that works to inhibit sodium and chloride reabsorption. Therefore, the determination of hydrochlorothiazide levels is essential for quality control, whether as raw material, in pharmaceutical preparations, biological fluids, or mixtures. Search information on the determination of hydrochlorothiazide content was carried out through Google Scholar with the keywords "hydrochlorothiazide," "determination," "pharmaceutical preparation," "biological matrix," "mixture." The results showed that the levels of hydrochlorothiazide as a raw material could be determined by high-performance liquid chromatography (HPLC), capillary zone electrophoretic (CZE), micellar electrokinetic capillary chromatography (MEKC), capillary electrophoresis, chemiluminescence, voltammetry, and quantitative point tests. Hydrochlorothiazide in a pharmaceutical dosage form can be determined by high-performance liquid chromatography, spectrophotometric, electroanalytic, thin layer chromatography (TLC) methods, voltammetry, and capillary zone electrophoresis. Hydrochlorothiazide in urine is determined by electrochemical method, and hydrochlorothiazide in human blood plasma is determined by liquid chromatography method. In contrast, the hydrochlorothiazide in mixtures with other substances can be determined using voltammetric methods and high-performance liquid chromatography.