A method of designing diffuser vanes in a centrifugal compressor comprising a diffuser and an impeller concentrically rotatable relative to the diffuser about an axis , the method consisting of the following steps carried out in the following order: a) providing to a computer processor an initial two-dimensional diffuser vane layout including initial diffuser vane peripheries circumferentially spaced about the axis , the initial two-dimensional diffuser vane layout being a layout of initial diffuser vanes in two dimensions and representing a configuration of the initial diffuser vanes as viewed axially (2-2) at a plane that is orthogonal to the axis and that extends through vanes of the impeller; b) using a computer processor, rotating, in said plane, the initial diffuser vane peripheries about the respective leading ends thereof in a direction opposite to a direction of rotation of the impeller relative to the diffuser and by an angle of from greater than 0 to about 30 degrees, to produce rotated diffuser vane peripheries having offset trailing ends relative to trailing ends of the initial diffuser vane peripheries ; c1) using the computer processor, circumferentially shifting, in said plane, the rotated diffuser vane peripheries about the axis to produce shifted diffuser vane peripheries , and whereby leading ends of the shifted diffuser vane peripheries are offset from the leading ends of the initial diffuser vane peripheries ; c2) wherein the leading ends of the shifted diffuser vane peripheries have the same radii as the leading ends of the initial diffuser vane peripheries; and d) using the computer processor, forming the diffuser vanes in a three-dimensional configuration by spacing the shifted diffuser vane peripheries from the corresponding initial diffuser vane peripheries in the direction of the axis and by generating diffuser vane surfaces connecting the shifted diffuser vane peripheries to the corresponding initial diffuser vane peripheries to produce diffuser vanes in a twisted configuration extending from leading edges to trailing edges thereof. a) providing to a computer processor an initial two-dimensional diffuser vane layout including initial diffuser vane peripheries circumferentially spaced about the axis , the initial two-dimensional diffuser vane layout being a layout of initial diffuser vanes in two dimensions and representing a configuration of the initial diffuser vanes as viewed axially (2-2) at a plane that is orthogonal to the axis and that extends through vanes of the impeller; b) using a computer processor, rotating, in said plane, the initial diffuser vane peripheries about the respective leading ends thereof in a direction opposite to a direction of rotation of the impeller relative to the diffuser and by an angle of from greater than 0 to about 30 degrees, to produce rotated diffuser vane peripheries having offset trailing ends relative to trailing ends of the initial diffuser vane peripheries ; c1) using the computer processor, circumferentially shifting, in said plane, the rotated diffuser vane peripheries about the axis to produce shifted diffuser vane peripheries , and whereby leading ends of the shifted diffuser vane peripheries are offset from the leading ends of the initial diffuser vane peripheries ; c2) wherein the leading ends of the shifted diffuser vane peripheries have the same radii as the leading ends of the initial diffuser vane peripheries; and d) using the computer processor, forming the diffuser vanes in a three-dimensional configuration by spacing the shifted diffuser vane peripheries from the corresponding initial diffuser vane peripheries in the direction of the axis and by generating diffuser vane surfaces connecting the shifted diffuser vane peripheries to the corresponding initial diffuser vane peripheries to produce diffuser vanes in a twisted configuration extending from leading edges to trailing edges thereof. <EOS>