Inelastic neutron time-of-flight spectra from polycrystalline cesium were measured at 50, 100, and 290 K for a large variety of momentum transfers $Q$ and energy transfers $\ensuremath{\omega}$. Born-von K\'arm\'an models were fitted to the resulting ($Q, \ensuremath{\omega}$) topography. These models were used to calculate the phonon dispersion curves and the phonon densities of states. The results confirm theoretical predictions. The elastic constants ${c}_{44}$ and ${c}^{\ensuremath{'}}$ determined from the measured data agree with ultrasonic results.