Objective. To study the relationship between personality type and variation of plasma peptides in pilots with neurosis. Method. A case-control study was used. 124 male pilots were evaluated with Eysenck's personality checklist, and then level of certain plasma peptides, such as vasoactive intestinal peptide (VIP), beta-endorphin (beta-EP) and angiotensin-II (A-II) were determined. Result. There were significant difference in personality characteristics and personality types between pilots with neuroses and the control. The contents of VIP and beta-EP in plasma showed visible difference between disease group and control. Content of beta-EP in those with inner-unstable type personality was lowest among all the various types. Conclusion. Personality characteristics were different between pilots with neurosis and controls. Levels of VIP and beta-EP in disease group were lower than those in the control. Different personality types had different levels of beta-EP in pilots with neurosis.