With this report MSF aims to raise awareness and express concerns about the impact of the current detention system on the mental health and wellbeing of migrants and asylum seekers arriving in Greece. The report documents the unacceptable living conditions in the three detention centers where MSF intervened (Pagani in Lesvos, Filakio in Evros and Venna in Rodopi) and presents data from psychological counselling sessions as well as individual testimonies. It shows that detention can exacerbate existing symptom*s and contribute to new traumas and psychological distress. The report often cites what newly arriving migrants told MSF teams about their experiences in detention. *No provisions are in place to meet the needs of vulnerable groups, including unaccompanied minors, infants, pregnant women, and people with disabilities. MSF urges the Greek authorities to carefully measure the impact of detention on the well being of migrants and asylum seekers and to seek alternatives to the detention of new arrivals. Thus, the plans by the Greek government to establish reception/screening centres for new arrivals should be implemented without delay. Conditions and services provided in the reception/screening centres should be in accordance with international standards.