The effect of the addition of SnO2 nano-particles on Bi-2223 phase formation has been studied. Tin oxide was added at different intervals of the synthesis process. It is shown that the addition of SnO2 inhibits the Bi-2223 phase formation regardless of when it is introduced to the system. SnO2 partially reacts with calcium to form the Ca2SnO4 phase. This phase is stable throughout the synthesis process. As a consequence, the formation of the Bi-2223 phase is compromised for the benefit of secondary phases such as Bi-2212, Ca2SnO4, Sr0.15Ca0.85CuO2 and Cu2SrO2. The c parameter of the Bi-2223 phase increases when tin is added. A possible explanation is a partial substitution of Cu2+ by Sn4+.