The main objective of the present study was to investigate factors related to seafarers' mental health. A sample of seafarers from 12 countries participated in the study. A list of stressors was used to assess both perception of exposure to these stressors and their subjective significance. The Symptom Checklist (SCL-90) was used to assess seafarers' mental health on 5 of 9 subscales: Depression, Anxiety, Hostility, Interpersonal Sensitivity, and Somatisation. Three significant findings emerged from the analyses. The first was that 3 types of stressors contribute significantly to mental health problems: (1) environmental factors (eg, vibration), (2) social problems (eg, bullying, homesickness, working alone), and (3) health problems (eg, physical injuries, viruses, and the illnesses). The second finding was that both stress and mental health issues determine seafarers' motivation for their work and their consideration regarding leaving the maritime industry. The third finding was that factors contributing to seafarers' consideration of leaving the industry were mainly related to social stressors such as isolation from family and friends, cultural differences at work, demands from supervisors, and bullying. Factors such as bad weather, working shifts, length of employment contract or a ban on disembarkment in ports were found to be relatively less important for seafarers as factors toward considering leaving the industry. The implications of these findings are discussed.