A mathematical model was proposed recently which appears to correlate the flow curves for several polymers in aqueous solution over a wide range of shear rates and concentrations. New data for several nonaqueous systems as well as data from literature sources support the idea that the same equation can be applied to nonaqueous solutions. The equation relates relative viscosityηrat shear rateγ̇and shear stress τ to two parameters, the zero‐shear viscosityηroand the power input at the inflection pointBas follows:log ηr/log γro=0.68−0.32 erf[log(rγ̇/B)/2.272]whereerf(q)is the error function ofq. The parameterBappears to be a function of intrinsic viscosity but is not sensitive to polymer type or concentration. A comparison is made which indicates that the proposed model has advantages over other two‐parameter flow equations for real polymer systems where concentration is varied.