This study examines a possible use of ozone channel measurements around 9.7 micron from geostationary satellites for determining cloud top height of deep convective clouds over the tropical latitudes. We determine the cloud top heights using Meteosat-8 measurements over the infrared window (IRW) and H₂O, CO₂, O₃ absorption bands with an aid of radiative transfer calculations. NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research) reanalysis data were used as inputs to the radiative transfer calculations. Using cloud top heights from collocated CloudSat observation as a reference, cloud top heights determined from IRW channel alone, H₂O-IRW channel combination, and CO₂-IRW channel combination are compared with results from the new combination of O₃ and IWR channels to see if there is any improvement of cloud top assignment, due to the inclusion of ozone channel, compared to other methods. We also discuss what degree of uncertainties is caused by the temporal and spatial variations of total ozone amount when cloud height is estimated from O₃-IRW combination method.