Detailed studies on asphaltenes from Indian sources are scarce. In this study, nC7 asphaltenes were extracted from an atmospheric tower bottom and a low waxy crude oil using IP143-based method and characterised using elemental analysis, nuclear magnetic resonance, Fourier-transform infrared spectroscopy, matrix-assisted laser desorption-time of flight mass spectroscopy, X-ray diffraction, and scanning electron microscopy. Results show that both asphaltenes differ widely in structures and molecular weights. It was deduced that both asphaltenes might have formed from kerogen degradation process resulting in higher oxygen content. Lower molecular weight and structural parameters (NMR) of atmospheric tower bottom asphaltene could be due to degradation of aliphatic part during preheating before atmospheric distillation process. Although dispersed, the XRD derived aromaticity of petroleum asphaltenes seems to vary inversely with stacking height and average diameter of the aromatic sheets, possibly due to compact structure of the cluster resulting from decreased stack height. Copyright © 2021 Inderscience Enterprises Ltd.