An examination of the transition level at which the ionospheric ions O+ and H+ are equal in concentration has been carried out by using the retarding potential analyzer data from the Ogo 6 satellite. Between dip latitudes of 0 ¿ and 50 ¿ the transition level shows a much pronounced latitude dependence during solar maximum than during solar minimum. The longitude dependence of the transition level features indicates the roles that zonal and meridional F region winds might play in the distribution of O+ and H+ in the low- and mid-latitude ionosphere.