Seasonal variations in fly ash collected from the electrostatic elctrostatc precipitator of a thermal power plant over a period of a year have been studied in parameters of (i) particle size, (ii) per cent silicate, (iii) haemolysis and (iv) contents of Ni, Pb, Mn, Zn, Hg, Cd, Mg, Na, Fe, Ca, K, Cu, Sr, As, Se, Co and Cr. Monthly variations were noted in the above parameters.