A mixture of soybean oil and hexane and ultrapure water containing a surfactant were injected into hexane-resistant glass capillary microfluidic devices to generate monodisperse oil/water emulsions. The diameter of the oil droplets was adjusted to be within the range of 2.7 15.6 mu m by changing the water phase flow rate. By evaporation of hexane dissolved in the droplets, monodisperse soybean oil emulsions with droplet diameters of 0.5-3.1 mu m were prepared. The present method is useful for the preparation of monodisperse emulsions with small droplets and could be used to prepare emulsions with smaller droplets by increasing the hexane concentration.