Objectives Disaster medicine research generally lacks control groups. This study aims to describe categories of diagnoses encountered by the Belgian First Aid and Support Team after the 2010 Haiti earthquake and extract earthquake-related changes from comparison with comparable baseline data. The hypothesis is that besides earthquake-related trauma, medical problems emerge soon, questioning an appropriate composition of Foreign Medical Teams and Interagency Emergency Health Kits. Methods Using a descriptive cohort study design, diagnoses of patients presenting to the Belgian field hospital were prospectively registered during 4 weeks after the earthquake and compared with those recorded similarly by Médecins Sans Frontières in the same area and time span in previous and later years. Results Of 7000 triaged postearthquake patients, 3500 were admitted, of whom 2795 were included and analysed. In the fortnight after the earthquake, 90% suffered from injury. In the following fortnight, medical diseases emerged, particularly respiratory (23%) and digestive (14%). More than 53% developed infections within 3 weeks after the event. Médecins Sans Frontières registered 6407 patients in 2009; 6033 in 2011; and 7300 in 2012. A comparison indicates that postearthquake patients suffered significantly less from violence, but more from wounds, respiratory, digestive and ophthalmological diseases. Conclusion This is the first comparison of postearthquake diagnoses with baseline data. Within 2 weeks after the acute phase of an earthquake, respiratory, digestive and ophthalmological problems will emerge to the prejudice of trauma. This fact should be anticipated when composing Foreign Medical Teams and Interagency Emergency Health Kits to be sent to the disaster site.