A new tetragonal phase with lattice parametersa=9·07 Å andc=21·9 Å has been discovered by electron diffraction. The space group determined by combining conventional and convergent beam electron diffraction is I4/mmm. The approximate composition obtained from X-ray dispersive analysis is Al80Cu5Fe15. It coexists with an incommensurate composite phase which consists of two subcells. The sublattice parameters area1=a,c1≈1/7c=3·14 Å anda2=a1/$$2,c2=3·71 Å. The structural and compositional relationships between the incommensurate phase and the commensurate phase are discussed.