A novel methanogenic strain, CaP3V-MF-L2A(T), was isolated from an exploratory oil well from Cahuita National Park, Costa Rica. The cells were irregular cocci, 0.8-1.8 mu m in diameter, stained Gram-negative and were motile. The strain utilized H-2/CO2, formate and the primary and secondary alcohols 1-propanol and 2-propanol for methanogenesis, but not acetate, methanol, ethanol, 1-butanol or 2-butanol. Acetate was required as carbon source. The novel isolate grew at 25-40 degrees C, pH 6.0-7.5 and 0-2.5% (w/v) NaCl. 16S rRNA gene sequence analysis revealed that the strain is affiliated to the genus Methanofollis. It shows 98.8% sequence similarity to its closest relative Methanofollis ethanolicus. The G + C content is 60.1 mol%. Based on the data presented here type strain CaP3V-MF-L2A(T) (= DSM 113321(T) = JCM 39176(T)) represents a novel species, Methanofollis propanolicus sp. nov.