The series BaBi1-xTaxO3 (0 <= x <= 0.5) has been synthesized by traditional solid-state reactions. Their structures are analyzed by the combinational use of X-ray, neutron, and converged-beam electron diffractions. They all crystallize in P1. FTIR and Raman data confirm that an inversion center is absent in the crystal structure of the series BaBi1-xTaxO3 (0 <= x <= 0.5). No obvious P-E (polarization-electrical field) loops are observed for them.