An alkaliphilic actinomycete strain, designated YIM 80379T, was isolated from a soil sample collected from the eastern desert of Egypt and subjected to polyphasic taxonomy. The strain produced substrate and aerial mycelia on different media, with an optimum pH for growth of 9.5-10 and scarce or no growth at pH 7. Strain YIM 80379T contained meso-diaminopimelic acid, no diagnostic sugars, type PIII phospholipids and MK-10(H6) and MK-10(H8) as the predominant menaquinones. All of these characters assign isolate YIM 80379T consistently to the genus Nocardiopsis. This was confirmed by 16S rDNA analysis. It can be differentiated from all Nocardiopsis species with validly published names by phenotypic characteristics, phylogenetic analysis and DNA-DNA hybridization results. On the basis of polyphasic evidence, a novel species, Nocardiopsis alkaliphila sp. nov., is proposed. The type strain of the species is YIM 80379T (=CCTCC AA001031T=DSM 44657T).