The time variation of the electrostatic potential of a plane electrode ionization chamber, due to the motion of electrons in the uniform field, depends on the drift velocity of electrons and the attachment of the electrons to the gas in the chamber. If the pulse is examined with a linear pulse amplifier having suitable integration and differentiation time constants, the pulse height will be a simple analytical function of the attachment coefficient and the electron drift velocity. This information has been used to develop a pulse method of measuring electron attachment. In one section of a plane electrode ionization chamber the pulse height due to the motion of electrons, produced by alpha particle ionization, is measured. Drift velocity of electrons is measured in another part of the same ionization chamber. These two measurements furnish data from which the attachment coefficient is calculated. Results for trace amounts of oxygen in argon will be presented.