The effect of base oil composition on lubricant properties has been studied to better understand low-temperature rheology, oxidative stability, and other physical properties. A simple approach has been adopted using low-temperature rheology to develop a multi-linear regression model to estimate Brookfield viscosity. Six base oils from A-PI groups II and III were studied using different nuclear magnetic resonance spectroscopy methods. One method involved determination of average structural parameters from quantitative C-13 NMR data, while the other method involved measurement of spin-lattice relaxation times at variable temperatures. The structural information obtained from these two methods was used to develop meaningful correlations for low-temperature, oxidative, and physical properties of these base oils. The study suggests that a deeper knowledge of chemical composition will help in selecting base oils to meet future product specifications.