Abstract: A diffuser for association with a centrifugal compressor includes a circumferentially disposed array of like, individual diffuser vanes each having integrally formed opposed flange pairs thereon joined by a bridge segment having a continually increasing depth from an inlet end of each of the vanes to the outlet end thereof. Adjacent ones of the vanes have their flange pairs juxtaposed to form a three-dimensional air flow passage between each of the vanes and wherein each vane has a spiral formed inlet wall pair extending radially inwardly at the inlet of each vane to form a spiral configured open inlet path into each of the three dimensional flow passages; the individual vanes being held in the circumferentially disposed array by spaced apart side support plates and fastening means directed through each of the side support plates and the bridge segments of each of the vanes.