  We study second order relativistic viscous hydrodynamics in 4-dimensional
conformal field theories. We derive Kubo-type relations for second order
hydrodynamic coefficients in terms of 3-point stress tensor retarded
correlators. For N=4 super Yang-Mills theory at strong coupling and at finite
temperature we compute these stress tensor 3-point correlators, using AdS/CFT,
by evaluating real-time cubic Witten diagrams in the AdS-Schwarzschild
background. The small momentum expansion of the 3-point correlators in terms of
first and second order hydrodynamic coefficients is matched with the AdS
result. We arrive at the same expressions for the hydrodynamic coefficients
which multiply terms quadratic in the shear and vorticity tensors in the
hydrodynamic expansion of the stress tensor as did Bhattacharyya, Hubeny,
Minwalla and Rangamani \cite{Bhattacharyya:2008jc}. Our method extends the
results of Baier et al \cite{Baier:2007ix}, and allows for a unified treatment
of hydrodynamic coefficients, which are extracted from 2-, and now, 3-point
retarded stress tensor correlators in the AdS-Schwarzschild background.
