Title: Least-Squares Finite Element Methods. Abstract. It is well-known that the standard Galerkin method produces a unique approximating solution with the restriction of small meshsize when there is a unique solution for the continuous problem. On the other hand, it is easy to construct an example such that the standard Galerkin method fails to produce a unique solution. In this talk, I will present two least-squares methods which guarantee the existence and the uniqueness of the approximating solution without the restriction of small meshsize. Various error estimates with confirming numerics will be provided.