This article explores the irretrievable losses of the French army during the Napoleonic wars through analysis of the service records of soldiers stored in the French military archive (SHD, Vincennes, 20 YC). This source allows to estimate military losses much more accurately than individual reports, which help to sum up these losses. During the study, service records of the main part of the Napoleonic army, without guards and foreign regiments were reviewed. This is about 8,431 people. This representative sample allows to confirm the analysis carried out earlier by a French historian Houdaille, who estimated the total deadweight loss of the French army during the Napoleonic wars to nearly 900,000 people.