The density ρ and the dynamic viscosity η of the ternary mixture heptane+methylcyclohexane+1-methylnaphtaiene were measured at 303.15, 323.15 and 343.15K at atmospheric pressure for molar fractionsxi=0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875 and 1 (with Σi=13xi= 1). The experimental data for η and ρ (135 values) can be used to evaluate the excess volumeVEand the excess energy of activation for viscous flow ΔGE. The density is modelled over the entire experimental domain of composition and temperature with an absolute average deviation of 0.03% and the dynamic viscosity with an absolute average deviation of 0.7%.