<p> According to Wohlers Report 2014, the worldwide 3D printing industry is now expected to grow from $3.07B in revenue in 2013 to $12.8B by 2018, and exceed $21B in worldwide revenue by 2020. With 3D printing rapidly evolving from a prototype commodity to a means to produce full production items, lattice structures are becoming of great interest due to their superior structural characteristics and lightweight nature. Within design, lattice structures have typically been defined by preset beam configurations within a cube. Certain configurations have been proven analytically to be optimal for certain load functions, but never has there been optimization performed to discover or verify the optimal lattice shapes and sizes within a predefined cubic space. By performing optimization on these cubic cells, a design guideline can be created for designers of lattice structures. In this thesis, several lattice configurations are analyzed both from a micro level (single unit cell) as well as a macro level (a simple series of unit cells). Optimization is performed with respect to stiffness and compliance to identify strategic configurations for bending, torsion, compression and tension. Only cubic base cells are analyzed (i.e. no hexagonal). Knowing optimal lattice configurations from a structural standpoint enables designers to further reduce weight and increase structural efficiencies when designing for additive manufacturing. The results of this study yield a well-defined guideline for design engineers to utilize when lattice structures are incorporated in a structural design. With this design guideline information available to design engineers, further utilization of lattice structures can be exploited by efficiently applying strategic unit cell configurations to the overall design.</p>