The Delta(1232) Resonance in Chiral Effective Field Theory

I discuss the problem of formulating the baryon chiral perturbation theory ($\chi$PT) in the presence of a light resonance, such as the $\mathrm{\Delta }(1232)$, the lightest nucleon resonance. It is shown how to extend the power counting of $\chi$PT to correctly account for the resonant contributions. Recent applications of the resulting chiral effective-field theory to the description of pion production reactions in $\mathrm{\Delta }$-resonance region are briefly reviewed.