The cross-section for resonant electron capture in oxygen has been measured by means of a Lozier apparatus. The value obtained, 2∙25 ± 0∙3 x 10
-18
cm
2
at 6∙7 eV, has been employed to calculate the attachment cross-sections to be expected at various mean energies in electron swarm conditions, assuming a Maxwellian distribution of velocities, and it has been shown that all previous attachment coefficient values are compatible with the resonant capture. Reasons have been advanced for doubting the accuracy of the Tate & Smith values of positive-ion cross-sections at lower electron energies.