Densities of the binary systems of 1,2-dimethylbenzene with ethyl acrylate (EA), butyl acrylate (BA), methyl methacrylate (MMA), and styrene have been measured as a function of the composition, at 298.15 K and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube densimeter. The calculated excess volumes (V-E) were correlated with the Redlich-Kister equation. The excess volumes are positive for the binaries of o-xylene with MMA and styrene, and negative for o-xylene + butyl acrylate. All systems present small deviations from ideality; the system o-xylene + ethyl acrylate is closest to ideality.