This paper reports viscosity data for the binary system 1, 1, 1,2-tetrafluoroethane (HFC-134a), x(1), +tetraethylene glycol dimethylether (TEGDME), 1 - x(1). The measurements (200 data points) were obtained at various pressures (between 10 and 100 MPa) in the homogeneous liquid state from T= 293.15-373.15 K. The measurements have been carried out with a failing body viscometer for four molar fractions x(1) =(0.28, 0.44, 0.63 and 0.88). The density values of this system were interpolated from previous results obtained at the laboratory. All of the available viscosity data, including pure HFC-134a and pure TEGDME (both previously studied at the laboratory), have been correlated using several viscosity models (mixing rules, self-refrencing model, hard-sphere theory, friction theory and free volume model). The resulting models are presented and discussed in this work. (c) 2005 Elsevier B.V. All rights reserved.