The volumetric properties of seven (water + ionic liquid) binary mixtures have been studied as a function of temperature from (293 to 343) K. The phase behaviour of the systems was first investigated using a nephelometric method and excess molar volumes were calculated from densities measured using an Anton Paar densimeter and fitted using a Redlich-Kister type equation. Two ionic liquids fully miscible with water (1-butyl-3-methylimidazolium tetrafluoroborate ([C(1)C(4)Im][BF4]) and 1-ethyl-3-methylimidazolium ethylsulfate ([C(1)C(2)Im][EtSO4])) and five ionic liquids only partially miscible with water (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C(1)C(2)Im][NTf2]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C(1)C(4)Im][NTf2]), 1-butyl-3-methylimidazolium hexafluorophosphate ([C(1)C(4)Im][PFG]), 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C(1)C(4)Pyrro][NTf2]), and butyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([N-4111][NTf2])) were chosen. Small excess volumes (less than 0.5 cm(3) mol(-1) at 298 K) are obtained compared with the molar volumes of the pure components (less than 0.3% of the molar volume of the pure ionic liquid). For all the considered systems, except for ([C(1)C(2)Im][EtSO4] + water), positive excess molar volumes were calculated. Finally, an increase of the non-ideality character is observed for all the systems as temperature increases. (C) 2009 Elsevier Ltd. All rights reserved.