Introduction: The prevalence of psychiatric morbidity is high among incarcerated individuals. Severe mental disorder is five to ten times higher among prisoners compared to the general population. Several factors are held to be responsible for the high prevalence of depression in prison: mainly poor living conditions (narrow room, loss of privacy), limited interpersonal relationships, and lack of mental health access. Inmates are at increased risk of all-cause mortality, suicide, self-harm, violence, and victimization while those with mental disorders are involved in conflicts and are more likely to be charged with prison rules. Purpose: To explore depression among male inmates. Methods and material: In the study, 101 male inmates were enrolled. Data were collected by the completion of a “self-rating depression scale (SDS)-Zung” which included participants’ characteristics. The statistical significance level was p
< 0.05. Results: Of the 101 participants, 51.4% of inmates were under 40 years old, 54.5% were married, 45.6% had been convicted of homicide and 38.6% had a life sentence. Normal depression levels were experienced by 62.4% of the participants, while 21.8% were mildly depressed, 14.9% were moderately depressed and 1.0% severely depressed. Foreign prisoners had statistically significant higher scores of depression compared to Greeks (median 48 vs. 45, p
= 0.012); those suffering from a chronic disease compared to those who did not (median 48 vs. 45, p
= 0.038); those who had spent time in solitary confinement compared to those who had not (median 46 vs. 43.5, p
= 0.038) as well as those who had not considered harming themselves compared to those who had thought of it (median 46 vs. 44, p
= 0.017). Conclusion: Given that prison populations are marginalized and deprived of the rights that people in the community benefit from, establishing the prevalence of depression in male inmates and its associated characteristics may help to formulate recommendations for future prison health care services. Clinical, research, and policy efforts are needed to improve prison mental health.