The osmotic coefficients of methanol + LiCl, + LiBr, and + LiCH3COO were determined by the isopiestic method at 25 degrees C. NaI in methanol solutions up to 4.33 mol.kg(-1) were used as the isopiestic reference with osmotic coefficients calculated from vapor pressure data reported by Barthel and Tomasula. Experimental osmotic coefficient data are reliably represented by the Fitter model with and without the beta((2)), term. The parameters for these equations, along with the corresponding standard deviations, are presented for these systems. The set of Fitter parameters b = 3.2, alpha(1) = 2.0 may be used. Including the beta((2)) term with alpha(2) = 1.4 improves the fit for all of the investigated solutes, so that the standard deviations reduce from 0.015 to 0.006 for LiCl, from 0.009 to 0.005 for LiBr, and from 0.005 to 0.004 for LiCH3COO in methanol solutions at 25 degrees C.