Genomicus (http://www.dyogen.ens.fr/genomicus/) is a database and an online tool that allows easy comparative genomic visualization in>150 eukaryote genomes. It provides a way to explore spatial information related to gene organization within and between genomes and temporal relationships related to gene and genome evolution. For the specific vertebrate phylum, it also provides access to ancestral gene order reconstructions and conserved non-coding elements information. We extended the Genomicus database originally dedicated to vertebrate to four new clades, including plants, non-vertebrate metazoa, protists and fungi. This visualization tool allows evolutionary phylogenomics analysis and exploration. Here, we describe the graphical modules of Genomicus and show how it is capable of revealing differential gene loss and gain, segmental or genome duplications and study the evolution of a locus through homology relationships.