Background Three permanent military operations are established in French Guiana. The Cayenne medical unit is a French military search and rescue unit and provides MEDEVAC and CASEVAC for ill and injured soldiers. The main objective of this study was to describe the temporal trends of its evacuation missions over 10 years. The secondary purpose was to document the means used for these missions.

Methods This retrospective observational study included patients who were evacuated for a medical reason or an injury during military operations in French Guiana. We collected the data from the computerised registers the medical department had stored.

Results From 1 January 2010 to 31 December 2019, 1070 patients were included, representing a median annual incidence of 115 (IQR 91–122) evacuations. Of these, 602 (59%) were evacuated by helicopter, 214 (21%) by airplane, 182 (18%) by ambulance and 19 (2%) by pirogue.

Reasons for evacuation were diseases in 664 (62%) patients, non-battle injuries in 389 (36%) patients and battle injuries in 17 (2%) patients. Finally, 286 (29%) evacuations were MEDEVAC and 712 (71%) were CASEVAC.

Over the years, the increasing number of evacuations reached a maximum of 183 in 2018. Helicopter evacuations, once the primary mode of evacuation, have declined proportionately in favour of other means of evacuation.

Conclusion Evacuation missions by the Cayenne medical unit increased over the 10-year study period, while helicopter use decreased. This evolution is a response to the constraints of adapting military operations to fight against illegal gold mining in the Amazonian Forest. Improvement of the means and procedures allows provision of the best care to patients while ensuring the ongoing conduct of military operations.