The extent of thermal strain while wearing personal protective equipment (PPE) during care activities for Ebola virus disease patients has not yet been characterized. From January to March 2015, 25 French healthcare workers (HCWs) in Conakry, Guinea, volunteered to be monitored while wearing PPE using an ingestible thermal sensor. The mean (standard deviation) working ambient temperature and relative humidity were 29.6°C (2.0°C) and 65.4% (10.3%), respectively; the mean time wearing PPE was 65.7 (13.5) minutes; and the mean core body temperature increased by 0.46°C (0.20°C). Four HCWs reached or exceeded a mean core body temperature of ≥38.5°C. HCWs wearing PPE for approximately 1 hour exhibited moderate but safe thermal strain.