This study investigated the application of the speeded lexical decision task to L2 aural processing efficiency. One-hundred and twenty Japanese university students completed an aural word/nonword task. When the variation of lexical decision time (CV) was correlated with reaction time (RT), the results suggested that the single-word recognition task could be successfully applied to the L2 aural modality. However, when CV and RT were correlated with L2 listening ability, a statistically significant relationship was not found. It was concluded that the single-word word recognition task might not be suited to measuring L2 aural word recognition efficiency. (Contains 1 table.)