[en] The photoelectron angular distributions from autoionizing ns and nf Rydberg states of NO are presented. A striking dependence of the angular distribution on the rotational level in the excited Rydberg complex is observed: The sign of the asymmetry parameter β alternates for consecutive rotational levels. A multichannel quantum defect calculation shows qualitative agreement with the experimental results and indicates the role of predissociation in the decay of these Rydberg states