Acidic methanol esterification followed by gas chromatography (GC) with electron capture detection (ECD) was applied for the determination of the nine haloacetic acids in water. The main advantage of this method is the use of acidic methanol as the derivatization agent instead of the hazardous diazomethane. The recoveries, estimated at concentrations ranging from 0.5 to 30 microg/l, are high for eight of the nine haloacetic acids, with the only exception being monochloroacetic acid. However, problems with this compound have been reported with diazomethane derivatization methods as well. The detection limits of the method range from 0.01 to 0.2 microg/l.