  We study Wilson loops in the three-dimensional N=6 supersymmetric
Chern-Simons theory recently constructed by Aharony, Bergman, Jafferis and
Maldacena, that is conjectured to be dual to type IIA string theory on AdS_4 x
CP^3. We construct loop operators in the Chern-Simons theory which preserve 1/6
of the supercharges and calculate their expectation value up to 2-loop order at
weak coupling. The expectation value at strong coupling is found by
constructing the string theory duals of these operators. For low dimensional
representations these are fundamental strings, for high dimensional
representations these are D2-branes and D6-branes. In support of this
identification we demonstrate that these string theory solutions match the
symmetries, charges and the preserved supersymmetries of their Chern-Simons
theory counterparts.
