A diffuser-deswirler for a gas turbine engine is provided. The diffuser-deswirler includes an inner shell and an outer shell spaced apart and configured for receiving a flow of compressed air from a compressor of a gas turbine engine. A plurality of vanes extend between the inner shell and the outer shell to define a plurality of fluid passageways and a splitter extends along the circumferential direction between adjacent vanes to split the flow of compressed air passing through the each fluid passageway. All of these components are manufactured as a single monolithic piece and are configured for diffusing and deswirling compressor air before passing it to a combustor for an improved combustion process.