There is a growing interest in Korean government to add bio-ethyl tert-butyl ether (bio-ETBE) in suboctane gasoline to reduce dependence on fossil fuel based transportation gasoline. The development of bio-ETBE analysis method is an urgent issue to protect illegal circulation of synthetic ETBE because synthetic ETBE and bio-ETBE are chemically indistinguishable even by using chromatography and conventional spectroscopy. This paper communicates the results of bio-ETBE determination from gasoline cocktail using low level liquid scintillation counting (LSC). The counts per minute (CPM) value increased linearly with the concentration of bio-ETBE, showing the correlation coefficient of 0.984.