The measurement of thermal conductivity of liquid dimethoxymethane had been performed at temperatures from (245 to 385) K and pressures from saturation pressure to 30 MPa. The thermal conductivity of the mixtures of dimethoxymethane + diesel fuel had been measured in the temperature range from (275 to 375) K and in the pressure range from (5 to 30) MPa with dimethoxymethane mass fractions of 0.05, 0.10, and 0.15. The transient hot-wire method with a single bare platinum hot wire was used. The experimental data of pure dimethoxymethane and the mixtures with diesel fuel, which had an estimated expanded uncertainty of +/- 2.0 % with the coverage factor k = 2, had been correlated as functions of temperature, pressure, and mass fraction, respectively.