Human adenoviruses (HAdVs), characterized with naked dsDNA, infect humans with a wide range of pathologies having mild effects to death. Discoveries have led scientists to use HAdVs for targeted therapeutics and as vector for vaccinations. This study will increase the understanding of species of human adenoviruses and will reveal their evolutionary relationship. There are 56 types of HAdVs divided in seven species, based originally upon their antigenicity, but are increasingly being classified according to genome composition, homology and organization. A protein sequence analysis of hexon and DNA polymerase genes was performed and compared with current species definitions of the selected serotypes. Hexon protein is a principle component of adenovirus capsid and is responsible for antigenicity, whereas DNA polymerase is required for faithful replication of the adenovirus genome. Hexon and DNA polymerase sequences from canine and simian adenovirus were also used as outliers. Protein sequences were retrieved from NCBI and GenBank and aligned via ClustalW2 multiple alignment server. JalView and Phylodendron were used to observe ClustalW guide tree.