An interpolation formula is obtained for the transverse viscosity of a hydrogen plasma over a broad range of the collision parameter gamma and the degeneracy parameter beta . If the temperature T exceeds the ionization temperature T//0, this formula applies to arbitrary values of beta and GAMMA ; for T APP 1STH T//0, it describes a nearly collisionless plasma. The derivation makes use of asymptotic approximations valid for a nearly collisionless plasma. It also draws on numerical calculations of the properties of a single-component classical plasma.