Results of calculations of single-photon pulsed-field ionization of the 1 pi orbital of the X (1) Sigma(+) (v" = 0) ground state of CO leading to the A (II)-I-2 (v(+) = 0-2) excited ionic state are reported. Agreement between the calculated and measured specta is reasonable except for the A (II1/2)-I-2 (y(+) = 0) level which shows strong autoionization at larger positive Delta J transitions. Our studies show that : the direct photoionization of the 1 pi orbital is very atomiclike.