Background: The simian crease is a single crease on the palm. However it can be seen in normal persons, it can be together with different health conditions such as Down's syndrome, leukemia, Alzheimer's disease, and some psychological problems.Methods: Seventy-six Nigerian university students participated to the study. Participants were 45 men and 32 women who were 17-24 years of age. To get their self-esteem and depression scores were used the Rosenberg Self-esteem Scale and the Self Reporting Questionnaire (SRQ) 20 adapted from WHO was used, respectively.Results: There were no simian crease status-related significant differences in self-esteem scores. There was a simian crease status-related the significant difference in the depression scores in only female subjects. The average depression scores were 15.15 +/- 4.83 in females with a simian line and 11.06 +/- 5.09 in females without the simian line.Discussion: Sex-related differences in depression, higher scores in women than in men in the normal population, and the relationships between genetic factors and depression suggest that simian crease (single transverse palmar crease) may be an important factor in the pathogenesis of depression, especially in women.Conclusion: Therefore, the simian crease status can be taken into consideration in the diagnosis and clinical follow-up of depression, especially in women.