In this work, preliminary results on the capability of Silica Optical Fiber (SOF) sensors, coated by thin films of closed-end (CeSWCNTs) and open-end (OeSWCNTs) Single-Walled Carbon Nanotubes, tin dioxide (SnO2) and Syndiotactic Polystyrene (sPS), to detect low percentage of gaseous hydrogen at cryogenic temperatures are reported. A Time Division Multiplexing (TDM) approach has been employed in order to simultaneously perform the interrogation of all the fabricated sensors. Experimental results demonstrated the potentiality of the proposed configuration to sense gaseous hydrogen with concentration lower than the explosive limit in air, at very low temperatures (113 K). Especially closed ends carbon nanotubes and tin dioxide based sensors have demonstrated significant sensitivity together with good recovery and reversibility features. © 2006 Optical Society of America.