Booster structure is subjected during the boost phase to a number of dynamic environments which may affect the integrity of the overall structure. To perform a meaningful dynamic load or stability analysis, an accurate prediction of the dynamic characteristic of the structure is required. Due to the complexity of Titan III, it was felt that the analysis by itself was not sufficient to guarantee a successful flight. A 20% dynamically scaled model of the Titan III was constructed and a vibration survey conducted. Comparison of the results indicates in general a good correlation of the test and the analytical data in the first three lowest pitch, yaw, and longitudinal modes.