A novel dynamic nonequilibrium technique for the determination of Henry's law constant (HLC) of phenols based on pervaporation-flow injection (PFI) is described. A linear relationship between HLC and the amount of phenol measured by a detector in the acceptor line of a PFI system was demonstrated. This relationship was constructed using five frequently encountered phenols (phenol, 2,4-dimethylphenol, 2,4-dichlorophenol, 2-chlorophenol, and 2,3-dimethylphenol) and used for the determination of the HLC of three other phenols (2,4,6-trichlorophenol, 2-methylphenol, and 3-methylphenol). The HLC of all eight phenols were also determined by the single equilibrium static technique (SEST). Fairly good agreementwas observed between both techniques regarding the HLC of 2,4,6-trichlorophenol, 2-methylphenol, and 3-methylphenol. On the basis of the results obtained, it was concluded that the PFI technique offers considerable advantages over SEST in terms of precision, speed, labor intensity, and possibilities for automation.