The SO₂ deposition velocity over a canopy of irrigated rice paddy in a tropical area was evaluated using the Bowen ratio and Fick's equations. The experimental facilities were set up in Chachoengsao province in the central region of Thailand and data was collected for a period of one year. The results showed that the deposition velocity of SO₂ varies with the time of day, and it was highest around noon time and lowest at night. Furthermore, the value for the seasonal average of V_d was the highest in winter and the lowest in the rainy season. The obtained seasonal average values of V_d were 0.67, 1.25, and 1.51 cm/s in the winter, summer, and rainy seasons, respectively.