NABEECO, is a software tool for solving the network alignment problem. NABEECO stands for Network Alignment with BEE Colony Optimization and it utilizes the artificial bee colony computing strategies for solving the so-called Graph Edit Distance problem. Network Alignment is a computationally hard bioinformatics problem. It aims to find the ”best” one-to-one correspondence between nodes from two input networks without using any external knowledge, such as sequence similarity. In NABEECO the ”best” alignment is the one, which has the lowest graph editing cost. Applied to Protein-Protein Interaction (PPI) networks, Network Alignment, finds its applications in the validation of interactions and the prediction of new ones, as well as for extracting conserved subnetworks in a set of given PPI networks. Network Alignment is a novel basis, in addition to DNA and amino acid sequence similarity, for further interspecies network analysis in drug development, including (functional) knowledge transfer between species