�In the present work a theoretical investigation of the cyclic operation of the radial flow solid desiccant dehumidifier has been reported. A mathematical model has been developed to predict the effect of air inlet conditions (humidity, temperature and flow rate) as well as bed design parameters on the desiccant bed dynamic performance during cyclic operation. The results show that, lower values of the humidity of process air at bed exit could be attained with increase in regeneration temperature, and desorption time decreases with increase in regeneration temperature. On the other hand, the adsorption time increases with increase in regeneration temperature. Also, it was found that, the adsorption time increases with the decrease in the required degree of dehumidification (wo/wi), and the ability of the bed to adsorb the moisture from air increases as the inlet air temperature decreases.