Abstract: An epoxy resin based powder coating composition which comprises: (A) 100 parts by weight of a mixed epoxy resin having a softening point of 60.degree.-80.degree. C. which consists of 50 to 70 wt. % of a bisphenol A expoxy resin having a number-average molecular weight of 800 to 1,800 and 30 to 50 wt. % of a cresol novolak epoxy resin; (B) 5 to 80 parts by weight of a novolak resin; (C) 0.5 to 5 parts by weight of triphenylphosphine; (D) 60 to 200 parts by weight of an inorganic powder having an average particle size of 0.5 to 75 um; and (E) 0.01 to 2 parts by weight of a microfine silica powder having an average particle size of 1 to 100 nm.The epoxy resin based powder coating composition can be coated on electrical and electronic components at 90.degree.-100.degree. C. with retaining the high moisture resistance, storage stability and free-flowing properties.