Excess molar volumes have been measured by means of a continuous-dilution dilatometer for (1-methyl-2-pyrrolidinone + benzene, toluene, o-oxylene, m-xylene, p-xylene, ethylbenzene, or styrene) at T = 298.15 K. The V-m(E) values were negative over the entire range of composition for all the binary mixtures. V-m(E) (minimum) and V-m(E) (x=0.5) values of this series decrease in the sequence : C6H5CH=CH2 > C6H5CH3 > p-C6H4(CH3)(2) > C6H6 > m-C6H4(CH3)(2) > o-C6H4(CH3)(2) approximate to C6H5CH2CH3. The results were compared with the results of the binary mixtures containing other polar liquids, and show that the interactions between 1-methyl-2-pyrrolidinone molecules and the above-noted aromatic hydrocarbon molecules are very strong.