Renormalization of the K_{e3} Form Factor

The renormalization of the $K_{e3\mathrm{}}$ form factor by the strong SU(3)-nonconserving interaction is calculated from the Fubini-Furlan sum rule and an experimental determination of the derivative of the matrix element of the divergence of the strangeness-changing current. The calculated renormalization is in agreement with that determined from measurements of $\mathrm{ft}$ values in Fermi nuclear $\beta$ transitions and of the absolute rate for $K^{+}\to e^{+}{\pi }^0\nu$.