Abstract The determination of the physical parameters of the equatorial electrojet (EEJ) from Korhogo (Latitude +9.3; Longitude -5.4; Dip -0.67) during the period of 1993 to 1994 was carried out by data of ionosonde IPS-42. The results made it possible to show that for a low average value of electron drift vertical approximately 5 m/s to the solstices and 6 m/s with the equinoxes in the morning, we obtained around midday a strong density of current of the EEJ (3.30A/km 2 in 1993 and 2.6A/km 2 in 1994). We determined during this study the values of the various electric fields intervening in the mechanism of formation of the EEJ. We showed the strong contribution of the polarization electric field in this phenomenon. The results gave the values of the zonal and polarization electric fields respectively 0.19mV/m and 3.5mV/m. The data of ionosonde IPS-42 made it possible to determine the density and intensity of current center of the EEJ (I 0 =231.11±53.7 A/km). We compared the intensity of the current in the center obtained with the ionosonde with that of the data on the ground. We obtained appreciably similar results