Simultaneous measurements of the OI 7774 Å and 6300 Å, N 2 + 3914 Å and Hβ 4861 Å nightglow emissions have been carried out at Cachoeira Paulista (22.7°S, 45.0°W; geomag. 11.9°S) since 1982, to study the response of the low-latitude ionospheric F-region to magnetic storms. The observations obtained during three magnetic storms (12–13 June 1983, 7–8 August 1983 and 28–29 March 1984) are presented and discussed. The N 2 + 3914 Å and Hβ 4861 Å emissions excited by energetic particle precipitation were observed during the main phase of strong magnetic storms. In contrast to the observations reported from mid-latitude stations by other investigators, no enhancements in the OI 7774 Å emission due to energetic particle precipitation were evident at our latitude. Even during strong magnetic storms, the OI 7774 Å intensity variations observed follow the variation of ( f 0 F2) 4, suggesting radiative recombination as the main excitation mechanism. The OI 6300 Å emission, on 7–8 August and 28–29 March, showed periodic intensity variations, which are associated with vertical oscillations of the ionospheric F-region plasma, as shown by the periodic height variations of the F-region seen from the ionograms obtained at the same location. Also, the OI 6300 Å North-South scanning observation on one occasion showed no meridional and longitudinal phase change, indicating the absence of propagation.