The object of the present paper is to characterize Cotton tensor on a 3-dimensional Sasakian manifold admitting -Ricci solitons. After introduction, we study 3-dimensional Sasakian manifolds and introduce a new notion, namely, Cotton pseudo-symmetric manifolds. Next we deal with the study of Cotton tensor on a Sasakian 3-manifold admitting -Ricci solitons. Among others we prove that such a manifold is a manifold of constant scalar curvature and Einstein manifold with some appropriate conditions. Also, we classify the nature of the soliton metric. Finally, we give an important remark.