Abstract: OPKFDDs (Ordered Pseudo-Kronecker Functional Decision Diagrams) are one of ordered-DDs (Decision Diagrams) in which each node can take one of three decomposition types: Shannon, positive Davio and negative Davio. OPKFDDs provide representations of Boolean functions with smaller number of nodes than other DDs. Since an appropriate decomposition type has to be chosen for each node, the size of the representation is decided by the selection of the decomposition type as well as the variable ordering of the diagram. To overcome the huge search space for an optimal solution, a genetic algorithm is proposed to generate OPKFDDs with the minimal number of nodes with experimental results.