Densities of binary liquid mixtures of N,N-dimethyl acetamide (DMA) + dimethyl sulfoxide (DMSO), DMSO + N - methyl-2-pyrrolidone (NMP), and DMA + NMP were measured over the entire composition range in the temperatures of 293.15 K and 313.15 K at atmospheric pressure. Based on this measurements, density deviations, Δρ, and excess molar volumes, V E , of binary mixtures were calculated and the same were fitted by Redlich-Kister equation. Binary adjustable parameters were obtained using Linear Least Squares Regression (Microsoft Excel 2016). The variations of derivative properties with temperature and composition were discussed. The densities of ternary mixtures DMSO + DMA + NMP were measured at 293.15 K and 313.15 K. According to experimental data, diagrams of density isolines at both temperature, density changes and excess molar volume at 293.15 K are constructed.