A study has been made of the piezoelectric constants of polycrystalline ferroelectrics of the barium titanate type and of their dependence on temperature of sintering of the ceramic and on the constant voltage applied. The measurements were made under static and dynamic conditions. It is shown that the piezomoduli of certain solid solutions in the systems Ba(Ti, Zr, Sn)O3 and Ba(Ti, Si, Sn)O3 are somewhat greater than those of barium titanate.