Measuring motor nerve conduction (MNC) in the hypoglossal nerve is an uncommon electrophysiologic study. However, this measurement can be easily performed with a wooden tongue depressor, to which a bipolar bar electrode is fixed by skin tape. We measured the MNC of the hypoglossal nerve in a patient with idiopathic unilateral weakness of the tongue. In the initial MNCs of the hypoglossal nerves, the CMAP amplitude was decreased and the latency was delayed in the lesion site when compared to the healthy site. In the follow-up study after 3 months, similar findings were found. Comparing the initial study with the follow-up one, however, the CMAP amplitude was increased and the latency was shortened in the lesion site. In conclusion, the MNC in the hypoglossal nerve is easy to measure and is useful for the evaluation of the hypoglossal nerve damage.