Vapor pressures of dimethyl ether were measured at temperatures from (233 to 399) K and at pressures from (54 to 5146) kPa. The uncertainties of measurements are within +/-5 mK on the ITS-90 scale for temperature and are within +/-0.7 kPa for pressure, respectively. With the new experimental data, a Wagner type vapor pressure equation of dimethyl ether was fitted. The absolute average deviation between the experimental data and the new Wagner equation is 0.043%, and the maximum deviation is 0.096%. The new vapor pressure equation of dimethyl ether was also compared with the published data.