The equilibrium deuterium pressure and the relative electrical resistance, R/Ro, as a function of D/Pd content during absorbtion-desorbtion processes of the Pd-D system, has been investigated at temperatures of 348, 373, 403 and 423 K up to a deuterium pressure of 3.3 MPa by a gas phase method. In the alpha single phase region for the absorbtion processes, R/Ro shows a very large increase with increasing D/Pd content. Achievement of R/Ro values depends on exact equilibrium pressures, and attains (R/Ro) a,,, values slowly after a long time. In the (alpha+beta) two-phase region, R/Ro shows almost constant values. In the beta single phase region, R/Ro again increases with increasing D/Pd content. In the beta phase region for the desorption processes, R/Ro gradually decreases with decreasing D/Pd content down to beta(min). On entering into the (alpha+beta) two-phase region, R/Ro values remain almost constant and show equal values to those of the absorbtion values. A small increase of R/Ro occurs from a D/Pd content of about 0.20, and maximum values attain at (alpha+beta)/alpha boundary compositions. In the alpha phase region, R/Ro values quickly decrease with decreasing D/Pd content. Increments of temperature show decreases of R/Ro values at different boundary compositions and in (alpha+beta) two-phase regions. Presently observed R/Ro behaviors for the Pd-D system show similarity with those reported previously for the Pd-H system.