1. Rheological relationships for high-temperature creep of metals in the region of reduced stresses should take account of the change in material volume from the instant of load application. In the case of a complex stressed state the relationships for describing the two primary creep stages are $$\begin{gathered} d\varepsilon _v^p = \psi (\sigma _0 ,\sigma _* ,\alpha _* ,\lambda )d\lambda ; \hfill \\ D_{d\varepsilon } = l_0 (\sigma _* )D_\sigma d\tau , \hfill \\ \end{gathered} $$ where σ0, σ*, α* are tensor invariants for true stresses. 2. In the case of a uniaxial stressed state (prolonged static loading) the linear approximation for devp/d with λ=const gives relationship (8) for creep strain ep, which may be written in the form of expressions (2) or (10) which are confirmed by numerous experimental data. 3. Relationships (9) and (10) are valid for a broad range of stresses and they are suitable for describing retarded creep with different strain portion for the grain boundary strain component. With relatively high stresses or moderate temperatures transient creep constants Δe1 and γ do not depend on external conditions.