Fano line shapes are reported in the excitation spectrum of the total fluorescence of NO trapped in Kr matrixes. They result from the homogeneous configuration mixing of the sharp valence vibrational bands B2P(v'=12,15,18)-X2P(v''=0) with the broadened multiphonon Rydberg vibrational bands C2P(v'=0,1,2)-X2P(v''=0). The main features of the spectrum are reproduced by a simulation. [on SciFinder (R)]