Ion‐chamber measurements of the photoionization produced by point‐to‐plane corona discharges in air, oxygen, and nitrogen (commerical grade) over a pressure range of 0.1 to 18 Torr are reported in this paper. The results are expressed in a generalized form that reduces the data for each gas to a single curve relating photoionization to pressure (p) times distance (R) from the discharge. The range of Rp values is between 1 and 550 cm Torr. Absorption coefficients are compared to those reported by other investigators by plotting absorption coefficient/pressure vs Rp. In air and oxygen the values fall along a common curve. These results indicate that relating the ion‐chamber currents to Rp in the manner described in this paper may provide a useful basis for calculating the photoionization produced by discharges in these gases.