The lifetime of the $E^3Pi_g(v=3)$ state of molecular iodine was measured in the gas phase at room temperature. The $E^3Pi_g$ state was selectively populated by two sequential nanosecond pulse laser excitation. Resolved molecular fluorescence for the $B^3Pi_u^+leftarrow E^3Pi_g$ was analyzed and the lifetime of the $E(v=3)$ state, measured using a time-correlated single photon counting technique, is to be $tau=21 (2)$ ns.