This work reports new measurements of the viscosity of some monoethylene glycol alkyl ether liquids: monoethylene glycol methyl ether (MEGME), monoethylene glycol ethyl ether (MEGEE) and monoethylene glycol iso-propyl ether (iso-MEGPE), up to 100 MPa at seven temperatures ranging from 293.15 to 353.15 K. The measurements at atmospheric pressure have been performed with an Ubbelohde-type glass capillary tube viscometer with an uncertainty of +/- 1%. At pressures up to 100 MPa the viscosity was determined with a falling-body viscometer with an uncertainty of +/- 2%. Using previous density data obtained at the laboratory, current measurements were used to study the dependence of the viscosity and of the molecular parameters of hard-sphere scheme and free-volume model on the molecular structure. (c) 2005 Elsevier B.V All rights reserved.