The well-known absolute reaction rate theory of Eyring was successfully extended to the accurate estimation of crude oil viscosities over a wide pressure range: from dead to live oil conditions. Two simple cubic equations of state (Soave or Peng-Robinson) were incorporated into the viscosity model to calculate all of the thermodynamic properties required within the Eyring's modeling framework. Satisfactory density and viscosity representations of various crude oils (with low-to-moderate molar masses) were achieved by using two tuning parameters valid over a wide pressure range.