Chlorobenzenes (CBs) and chlorophenols (CPs) in fly ashy discharged from several municipal solid waste incinerators (MSWI) were investigated in terms of total content and isomer distribution. The content of CBs and CPs was highest in the fly ash from S incinerator, which were 1040.7ng CB/g-fly ash and 1156.4 ng CP/g-fly ash. According to the experimental results, while all samples contained a large amount of the higher chlorinated CBs, was almost constant regardless of season. The quantities of CBs and CPs depended closely on the chemical composition of MSW. while the isomer distribution of CBs and CPs was constant throughout all the year round.