This article describes the technical performance and initial results for a new, two-piston, "multipass rheometer." Fluid is contained within a capillary by two servo-hydraulically controlled pistons. Both steady flow and oscillatory data can be obtained from the device with mean pressure as an independent adjustable variable. Steady and oscillatory data are presented for a silicone oil and a viscoelastic solution and certain data are compared with results obtained from a Rheometrics RDS-II mechanical spectrometer or with literature data. The results show that the multipass rheometer is capable of extending the experimental ranges of many conventional rheometers, particularly in terms of pressure control, high shear rates, and multiple, successive flow measurements.