The viscosity of liquid 2,3,4-trimethylpentane, 2,2,4-trimethylpentane, 2,2,4,4,6,8,8-heptamethylnonane, squalane, polyisobutylene (M = 500 g/mol), ethylbenzene, and 1,2-diphenylethane at elevated pressures was determined with a rolling ball viscometer. The viscosity measurements were performed at 298, 353, and 453 K and pressures up to 200 MPa with an accuracy of +/-2%. The results were described by an empirical equation as a function of pressure and temperature.