The production of BPSCCO-2223-multifilamentary tapes by the powder in tube method requires high quality precursor powders. The qualitative and quantitative phase composition of the precursor powders influence the current carrying capacity of the tapes. Different processing conditions during the precursor formation lead to different phase compositions and phase contents. A high level quality control has to guarantee a stable phase content. Up to the present phase composition of BPSCCO-2223-multifilamentary tapes has been calculated by the ratio of the strong (001) or (115) diffraction intensities for the Bi(Pb)-2212- and Bi(Pb)-2223-phases. This approach does not take into consideration secondary phases, preferred orientation or any solid solutions of phases present in the tapes. Rietveld refinement offers new possibilities for accurate quantitative phase analysis by XRD. Data sets - supported by a new Windows software package - were developed for different precursor powders and BPSCCO-2223-multifilamentary tapes. XRD combined with Rietveld refinement is an efficient, fast and user friendly toot for quality control of BPSCCO-2223 precursors and tapes.