Density and viscosity of 1-hexene (6), 1-heptene (7), 1-octene (8), 1-decene (10) and their binary, [25%(6) + 75%(10), 50%(6) + 50%(10), 75%(6) + 25%(10), 25%(6) + 75%(8), 50%(6) + 50%(8), 75%(6) + 25%(8), 50%(6) + 50%(10)] ternary [33,3%(6) + 33,3%(8) + 33,3%(10)] mixtures were simultaneously measured over the temperature range from 193 K to 465 K and at pressures up to 245 MPa using the hydrostatic weighing and falling-body techniques. The expanded uncertainty of the density, pressure, temperature, and viscosity measurements at the 95% confidence level with a coverage factor of k=2 is estimated to be 0.15%-0.30%, 0.05 %, 0.02 K, and 1.5% - 2.0% (depending on temperature and pressures ranges), respectively. Tait-type equation of state (EOS) for pure 6, 7, 8 and 10 was developed using the measured (p, ,T) data. Theoretically based Arrehenius - Andrade and Vogel - Tamman - Fulcher type equation with pressure dependent coefficients was used to describe the temperature dependence ofmeasured viscosities for pure olephins.