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.