Monoisomeric linear alkylbenzene sulphonates (LAB) are prepared and evaluated on a laboratory scale for enhanced oil recovery (EOR) applications. The effect of surfactant chain length has been studied using four compounds, 4 phi C-9, 4 phi C-10, 4 phi C-11 and 4 phi C-12 ABS, and it has been found that the plateau level increases linearly with increasing sulphonate chain length. Effect of the point of attachment of the benzene ring on the linear chain on adsorption has also been studied in two sets of experiments. In the first set, three phenylundecane isomers have been used and in the second set four phenyldodecane compounds isomers have been employed. Plateau adsorption levels for each of these compounds are determined through adsorption isotherms at the same experimental conditions. Linear increase in plateau adsorption level has been observed when the position of phenyl group is changed to the more central carbon atoms.