Introduction: The psychological and social impacts of disasters can undermine the long term well-being of the affected population. Well integrated and community-based mental health / psychosocial support (MHPSS) interventions can improve emotional, social and mental aspects of well-being. Professional understanding of effects of disasters, paired with post-emergency mental health (MH) awareness, can provide opportunity for improving community MH services. Problem statement: This prospective, semi-quantitative study evaluated the effectiveness of a community-based integrated MHPSS intervention by the Dutch international non-governmental organization (INGO) Cordaid in post-earthquake Haiti. Methods: Training on MHPSS issues was delivered to 115 non-specialized healthcare providers and 190 community psychosocial workers. The community-based MHPSS intervention was delivered to 115,191 direct beneficiaries. Data collection methods included quantitative community surveys with well-being, distress and resilience scales; a survey on satisfaction of training participants and multiple-choice knowledge tests. Results: MHPSS training reinforced the knowledge base of community psychosocial workers and non-specialized healthcare providers; a necessary prerequisite to the delivery of the community-based MHPSS intervention. The community-based MHPSS intervention resulted in improved well-being and resilience and reduced distress in targeted communities. Conclusions: The community based and integrated MHPSS intervention in Haiti was a feasible and much appreciated intervention that was relatively effective in a difficult disaster context. The intervention improved access to community MH care; psychosocial services; and general well-being of the affected population. This type of intervention may be reproducible in other post disaster environments, especially resource poor settings with neglected MH sectors.