This study investigated the impact of particle size on dissolution profile of rivaroxaban, a poorly water-soluble active pharmaceutical ingredient (API), from solid dosage form and the ability of dissolution method to detect this change. Particle size analysis (PSA) using laser diffraction with a wet dispersion technique, was developed and validated according to the guidelines. Dissolution study was performed according to the European Pharmacopoeia (Ph. Eur.) monograph for rivaroxaban tablets, using a validated dissolution method. The dissolution test was conducted in 900 mL of the medium at a rotation speed of 75 rpm for 30 min. The dissolution medium for 10 mg tablets consisted of sodium acetate (29.9 g), glacial acetic acid (16.6 mL) and sodium dodecyl sulphate (20 g) dissolved in 10 L of water and adjusted to pH 4.5. For 15 mg and 20 mg tablets, the composition was the same except for an increased sodium dodecyl sulphate concentration (40 g per 10 L). Analysis was performed using liquid chromatography (LC) with an end-capped octadecylsilyl silica gel column (5 μm, 250 mm × 4.6 mm) at 40 ℃. The mobile phase consisted of acetonitrile and water (55:45, V/V), with a flow rate of 1.2 mL/min, and detection was carried out at 249 nm. The results demonstrated a significant correlation between particle size and dissolution rate, highlighting the importance of controlling particle size in pharmaceutical development to ensure consistent drug release and bioavailability. Dissolution test successfully discriminated batches of finished product manufactured with different particle size of active pharmaceutical ingredient, even though prescribed media contained surfactant.