Computing Integrals over Polynomially Defined Planar Regions and Curves Michael Wester, Yuzita Yaacob, Stanly Steinberg Abstract: We use the cylindrical algebraic decomposition algorithm implemented in Mathematica to produce algorithms to analytically compute integrals over polynomially defined regions in the plane. We also produce an algorithm to compute integrals over the boundary of such regions and then implement the two dimensional version of the Green's theorem. The resulting software can solve many of the two dimensional integration problems in calculus textbook.