Although abundant literature data are available on liquid-liquid phase equilibrium for select hydrocarbon-water systems at ambient or near ambient temperatures, a deficiency exists for data at elevated temperatures. In this study, we sought to (a) evaluate existing mutual hydrocarbon-water liquid-liquid equilibrium (LLE) data, (b) develop an experimental apparatus capable of measuring accurately the hydrocarbon-water (LLE) mutual solubilities, and (c) perform measurements on the benzene-water, toluene-water, and 3-methylpentane-water systems. A continuous flow apparatus was utilized to measure the LLE mutual solubilities at temperatures ranging from ambient to 500 K, which is near the three-phase critical end point of the benzene-water and toluene-water systems. The well-documented benzene-water system was used to validate the reliability of the sampling and analytical techniques employed. Generally, the present measurements showed adequate agreement with available literature data. An error propagation analysis for the three systems indicates maximum expected uncertainties of 4% and 8% in the water-phase and organic-phase solubility measurements, respectively. This study provides valuable LLE mutual solubility data and demonstrates the efficacy of the experimental apparatus in making accurate measurements.