  We propose the exact S-matrix for the planar limit of the N=6 super
Chern-Simons theory recently proposed by Aharony, Bergman, Jafferis, and
Maldacena for the AdS_4/CFT_3 correspondence. Assuming SU(2|2) symmetry,
factorizability and certain crossing-unitarity relations, we find the S-matrix
including the dressing phase. We use this S-matrix to formulate the asymptotic
Bethe ansatz. Our result for the Bethe-Yang equations and corresponding Bethe
ansatz equations confirms the all-loop Bethe ansatz equations recently
conjectured by Gromov and Vieira.
