Summary This paper presents the density and viscosity measurements for a condensate sample, Athabasca bitumen, and Athabasca bitumen/condensate mixtures applicable for in-situ bitumen-recovery methods and pipeline transportation. The measurements for the densities and viscosities are reported at different temperatures (ambient to 200°C) and pressures (atmospheric to 10 MPa). For mixtures, a wide range of solvent fractions (5-50 wt%) is investigated. The data for the mixtures are also evaluated with predictive schemes as well as with correlation models representing certain mixing rules proposed in the literature. The results indicate that mixture densities are well represented by the excess-volume method, with an average absolute relative deviation (AARD) of 0.78%. The Bij model predicts the mixture viscosities with an AARD of 11.7%.