The contribution of dynamic surface tension (gamma(t)), obtained using the maximum bubble pressure method, on foamability and foam stability is presented for aqueous solutions of a series of polyoxyethylene dodecyl ethers; C12H25O(C2H4O)(n)H, where n = 5-53. In the shorter measuring time region (<1 s), the maximum rate of the decrease in the surface tension, (d gamma(t)/dt)(max) obtained from the gamma(t), increases with an increase in ethylene oxide (EO) units. The initial foamability, measured by the Ross-Miles technique, was correlated with the increase in the values of (d gamma(t)/dt)(max). However, in the longer measuring time region (>1 s), at which the dynamic surface tension approaches the meso-equilibrium (gamma(m)), gamma(m) decreased with a decrease in EO units. The degree of elongation of lamellae (L(lamellae)), measured by a laminometer, decreased with an increase in EO units. The residual foam stability, measured by the Ross-Miles techniques, was also correlated with the decrease in the values of L(lamellae). According to these techniques, the significance of the surface tension gradient for foamability is elucidated.