The microwave spectra of (PNO)-N-14-O-16 and its isotopomers (PNO)-N-15-O-16 and (PNO)-N-14-O-18 were observed in a dc glow discharge plasma of a mixture of nitric oxide and hydrogen gases over solid red phosphorus placed on the stainless steel electrode. Rotational transitions of the parent (PNO)-N-14-O-16 species were measured in the ground state as well as in the vibrationally excited nu(1) (PN str.), nu(2) (bend), and 2 nu(2) states. The l=0 substate of the 2 nu(2) state interacts with the nu(1) state through a Fermi resonance. The rotational constants determined for the ground states of the three isotopomers yield the substitution structure, r(s)(PN)=151.6516(87) pm and r(s)(NO)=119.5025(80) pm.