  We consider a process $K_{L e5} ( K_{L} \rightarrow \pi^{0} \pi^{0} \pi^{\pm}
e^{\mp} \nu )$ as a standard model background to the experiment $K_{L}
\rightarrow \pi^{0} \mu^{\pm} e^{\mp}$, which seeks for possible violation of
lepton family number. Using the lowest order chiral lagrangian, we find that
the branching ratio for $K_{L} \rightarrow \pi^{0} \pi^{0} \pi^{\pm} e^{\mp}
\nu $ to be $6.2 \times 10^{-12}$. A similar decay $K_{L} \rightarrow \pi^{\mp}
\pi^{\mp} \pi^{\pm} e^{\pm} \nu$ has a branching ratio, $1.7 \times 10^{-11}$.
