New results on the competition between autoionization and predissociation in the high Rydberg states of nitric oxide are presented. These results provide insight into the earlier work of Park ct al. [Phys. Rev. Lett. 76, 1591 (1996)] that shows evidence for substantial mixing between Rydberg series and ionization continua with even and odd orbital angular momenta (I). New data based on fluorescence-dip spectroscopy, detection of neutral predissociation products, and photoelectron spectroscopy suggest that the A＇(2) Sigma(+) and I-2 Sigma(+) dissociative valence states play an important role in this I mixing. Zeeman splittings observed in a magnetic bottle electron spectrometer also result in an improvement in the assignment of these high Rydberg states.