The phase change pattern of antiferroelectric and B-site ordered Pb(Yb1/2Nb1/2)O3 on doping ferroelectric and disordered Pb(Fe1/2Nb1/2) O3 has been examined. Initial x-ray diffraction and dielectric constant results show the reduction of the transition temperature with increasing x in (1-x)Pb(Yb1/2Nb1/2)O3 - (x)Pb(Fe1/2Nb1/2)O3. For 0.0 less-than-or-equal-to x less-than-or-equal-to 0.13, the antiferroelectric-paraelectric phase transition is relatively sharp, the low temperature crystal structure of the solid soluion may be analyzed based on an orthorhombic crystal structure. For 0.15 less-than-or-equal-to x less-than-or-equal-to 0.30, the low temperature crystal structure is pseudocubic, and the phase transition changes from a sharp to a diffuse one.