We add fundamental flavors to $ \mathcal{N}=2 $ Chern-Simons-matter theories living on M2 branes probing a Calabi-Yau four-fold singularity. This is dual, in the ’t Hooft limit described by IIA string theory, to the introduction of supersymmetric D6 branes wrapping AdS4 and a 3-cycle of the internal manifold. The resulting Chern-Simons theories remain conformally invariant, corresponding to the fact that the D6 branes lift to pure geometry in M-theory. The determination of the moduli space relies crucially on the 1- loop contributions to charges and OPE’s of monopole operators in these field theories. The general picture is determined for non-chiral and chiral flavors, and is illustrated in several examples.