This paper introduces a new software developed for building performance optimization. MOBO is a generic freeware able to handle single and multiobjective optimization problems with continuous and discrete variables and constraint functions. It can be coupled to many external (simulation) programs. It has a library of different types of algorithms (evolutionary, deterministic, hybrid, exhaustive and random), and is able to handle multi-modal functions and have automatic constraint handling. The input is fed by a GUI. The user can write the input by algebraic formulas using standard symbols. The output can be viewed by two graphs that show the progress of the optimization. A beta version of MOBO is available for download and use