There are no published reaction rates of O+ ions with O2, N2, and NO for ion temperatures in excess of 6000 K in the ionosphere. Yet, there are now documented cases of very strong perpendicular high-latitude ionospheric electric fields, with resulting ion temperatures well in excess of 10,000 K. We have therefore extended the calculations of O+ reaction rates to fields as high as 250 mV/m, that is, to ion temperatures as high as 30,000 K. In the process of presenting new formulae for the revised rates, we stress that at temperatures less than 6000 K, our new rates are entirely consistent with previously published values. The new rates are presented in order to allow ionospheric modelers to apply their composition calculations to highly disturbed conditions. ¿ 1998 American Geophysical Union