A magnetic tunnelling spin injection device (MAGTID) consisting of a stack of two ferromagnetic tunnelling junctions with access to the intermediate electrode has been developed. The layer structure is Co/A1203/NiFe/AI203/CO. The layers were deposited by dc-magnetron sputtering and the barriers were formed by ultraviolet-light assisted thermal oxidation. The performance of the upper and lower junctions within a stack were determined by current-voltage characteristics, the first derivatives (dV/dI vs. V) and the individual tunnelling magnetoresistances (TMR). A potential contact to an only 5.5 rim thick NiFe middle layer was successfully achieved. Using one junction in a stack as a spin injector and the second junction as a detector various magnetoresistance measurements were performed. The resistance of the detector junction was dependent on the magnetization of the common NiFe layer (parallel or antiparallel to the outer Co layers) and the injector current. The normalized TMR of the detector varied by up to 30%. This result will be discussed in the framework of non-equilibrium spin accumulation in the in the intermediate NiFe layer. For further improvement of the MAGTID we have studied Ta/Ni79Fe2,/Fe5oMnso/CoFe/A1203/CoFe/NiFe single barrier junctions using FeMn as an antiferromagnetic pinning layer. First results of these junctions will be presented.