We report a new mode of precipitation in a B19 martensitic Ti 50 Ni 30 Pd 20 shape memory alloy consisting of a central Ti 2 Ni(Pd) precipitate surrounded by an austenite area containing Ti 2 Pd(Ni) precipitates. The morphology and crystallography of the precipitation area is investigated using conventional and high resolution electron microscopy. In particular, the orientation relationship and the coherency strain between the Ti 2 Pd(Ni) precipitate and the surrounding retained B2 matrix are discussed. A study of local composition in relation with a ternary phase diagram using X-ray energy dispersive spectroscopy with a nanoprobe gives evidences of the formation mechanism.