At the present moment huge amount of experimental data on functions and interactions of 5-HT with peptide hormones AVP and OT has been collected. Systematization and analysis of this scattered information is necessary. The first stage of our work was to compile an information database comprising a huge list of sources mainly covering the period of 1960–2005. The structure of the database includes: influence direction, species, dose, administration, receptor mechanisms. Basing on this database an estimate of influences of 5-HT and the peptides has been performed. It was found that 5-HT via 1A, 2A/C and 4 receptors increases expression of OT in the PVN, hypothalamic OT secretion and its serum level. Stimultaneously, 5-HT can have an inhibitory effect on the OT-neurons activity in the hypothalamic PVN. OT exerts opposite effects on 5-HT in various CNS structures. It was found that OT reduces 5-HT in hypothalamus, mesencephalon and increases 5-HT in striatum. Analysis of serotonin-AVP interactions revealed that 5-HT agonists via 1C, 2A/C, 4 and 7 receptors stimulate AVP expression and secretion in the PVN. Moreover it was determined that 5-HT can decrease AVP in the median eminence of rats. Injection of melatonin or 5-metoxytriptamine inhibit AVP release. Investigation of AVP influence on 5-HT system revealed that this peptide potentiates 5-HT synthesis and release in the hippocampus. Basing on the results of numerous studies integrative scheme of interactions of 5-HT with AVP and OT was built up.