  We study \Omega-deformation of B-twisted gauge theories in two dimensions. As
an application, we construct an \Omega-deformed, topologically twisted
five-dimensional maximally supersymmetric Yang-Mills theory on the product of a
Riemann surface $\Sigma$ and a three-manifold $M$, and show that when $\Sigma$
is a disk, this theory is equivalent to analytically continued Chern-Simons
theory on $M$. Based on these results, we establish a correspondence between
three-dimensional $\mathcal{N} = 2$ superconformal theories and analytically
continued Chern-Simons theory. Furthermore, we argue that there is a mirror
symmetry between {\Omega}-deformed two-dimensional theories.
