Cytochrome P450 (CYP) enzymes are heme-containing monooxygenases that catalyze metabolisms of various endogenous and exogenous compounds. They constitute a superfamily of enzymes present in various organisms including mammals, plants, bacteria, and insects. CYPs are diverse and metabolize a wide variety of substrates, but their structures are largely conserved. In this study, bioinformatic analyses of CYP enzymes were performed in seed plants and other organisms' protein sequences, including 39 species of 19 different families. According to the conserved motifs obtained by MEME and MAST tools, four motifs were common in most seed plants. The structural and functional analyses of six selected species of seed plants and other organisms were investigated by ProtParam, SOPMA, Predotar 1.03, SignalP 4.1 and TMHMM 2.0 tools in ExPASy database. The tertiary structures of Arabidopsis thaliana as a sample of seed plants and five samples of other organisms were predicted by Phyre2 server using 2hi4.1.A" model (PDB accession code: 2hi4). The protein sequences were aligned with ClustalW algorithm by MegAlign (DNAStar Lasergene 12.1) and MEGA 6.06, then the phylogenetic tree was constructed using the neighbor-joining (NJ) method. In protein-protein interactions analysis by STRING 9.1 tool, six enriched pathways were identified in Arabidopsis thaliana and other species. According to the results, there is a high similarity among CYP proteins of different species in seed plants and other organisms, so they should be derived from a common ancestor. The obtained data provide a background for bioinformatic studies of the function and evolution of these proteins in seed plants.