A rapid and sensitive method using pressure-assisted electrokinetic injection (PAEKI) as the on-line sample enrichment technique and electrospray-tandem mass spectrometry as the monitor has been developed for the determination of four halogenated phenols, 2,4,6-trichlorophenol, 2,4-dichlorophenol, 2,3,4,6-tetrachlorophenol and tetrabromobisphenol A, in water samples. In 8-min of injection, the four halogenated phenols in water samples were enriched up to several thousand times. With the aid of a solid-phase extraction clean-up procedure, the method achieved a detection limit in the range of 7.4 to 37.1 ng L(-1) for the four phenols by multiple reaction monitoring in a negative mode. The overall recoveries for all four halogenated phenols in water samples were in the range of 68 to 114%. The good method repeatability has been demonstrated by the relative standard deviations (RSDs) of less than 10% for water samples spiked with standard mixtures. The four target phenols in all the water samples were below the detection limits.