In this paper we examine the correlation between neutral and charged pions mainly at 200 GeV/c in proton collisions. The events are divided into diffractive and nondiffractive categories. With this separation, the correlation between neutral and charged pions in either category is smaller than without the separation. The residual correlation can probably be accounted for by resonance production. A simple model is proposed involving the production of I=0 pairs of pions which can explain the bulk of the data. We also examine the multiplicity distribution of the nondiffractive events, which is nearly Poisson in nature. © 1982 The American Physical Society.