My talk will be divided into two parts: In the first I will present a novel
measure of chaotic scattering amplitudes.  For chaotic scattering the distribution function is given
by the β-ensemble of random matrix theory (RMT). We show that amplitudes of one highly
excited string (HES) state with two or three scalars in open bosonic string theory admit
this behavior. Quite remarkably this measure applies also to the distributin of non-trivial
zeros of the  Riemann zeta function.
The second part will be about deterministic Chaos in Integrable Models. We present
analytical and numerical evidences that classical integrable models possessing infinitely many
degrees of freedom exhibit some features that are typical of chaotic systems. We investigate
this phenomenon in the explicit examples of the KdV equation and the sine-Gordon model
and further provide general arguments supporting this statement