The results of recent studies of domain walls and their interaction with defects in BaTiO3, Pb(Zr, Ti)O-3, and BiFeO3 are discussed. The studies reveal why donor- and acceptor-doped Pb(Zr, Ti)O-3 behave differently, what is the role of stationary charged domain walls in enhanced properties of domain engineered BaTiO3 crystals, and give evidence of a large concentration of specific charged point defects within domain walls in BiFeO3 ceramics. (C) 2017 The Japan Society of Applied Physics