Excess volumes, obtained from density measurements at 298.15 K, are reported for binary mixtures of n-butyl methyl ether (C4H9OCH3) with the n-alkanes (CnH2n+2, n = 6, 7, 8, 10, 12, and 16). The results are compared with values calculated from the Flory theory with use of interchange-energy parameters derived from a previous analysis of excess enthalpy data. © 1990, American Chemical Society. All rights reserved.