Recording at a nanometer-scale on 3-phenyl-1-ureidonitrile (CPU) thin films is successfully conducted using scanning tunneling microscopy (STM) in ambient conditions. Recorded marks are written when a series of voltage pulses are applied between the STM tip and the freshly cleaned highly ordered pyrolytic graphite (HOPG) substrates. STM current–voltage (I–V) curves of the films show that the electric resistance in the recorded regions is much lower than that in the unrecorded regions. Standard four-point probe measurements indicate that the transition time of the transient conductance is 6 ns. It is suggested that CPU organic thin films have potential in the application of future data storage.