[en] Ultimate strength and shear wave velocity of dry, 50% saturated, and saturated Paintbrush tuff samples from the Nevada Test Site (NTS) are measured as a function of pressure up to 400 MPa. A linear relationship exists between the ultimate strength (tau) and shear modulus (μ) for the dry tuff at pressures from 0.1 to 20 MPa and from 100 to 300 MPa, with values of d tau/dμ; of about 1.25 x 10^-₂ and 2.6 x 10^-₂, respectively. At pressures between 20 and 100 MPa a linear relationship also exists with a much greater value of d tau/dμ, of about 9.9 x 10^-₂. For the half-saturated tuff, under undrained testing conditions, a similar linear relationship exists at pressures up to 20 MPa. At pressures between 20 and 300 MPa the data of the partially saturated tuff have too much scattering to deduce a meaningful relation. No such correlation can be found for the saturated tuff sample under undrained testing conditions. If similar relations could be found for other rock types and under other controlled experimental coditions, such as at a fixed pore fluid pressure (drained test) or temperature, then the results would be very valuable for the estimation of the in situ strength of rock masses