Available information suggests that there were about 500,000 deaths from all causes during the Spanish Civil War. An estimated 200,000 died from combat-related causes. Of these, 110,000 fought for the Republicans and 90,000 for the Nationalists. This implies that 10 per cent of all soldiers who fought in the war were killed.

It has been calculated that the Nationalist Army executed 75,000 people in the war whereas the Republican Army accounted for 55,000. These deaths takes into account the murders of members of rival political groups.

It is estimated that about 5,300 foreign soldiers died while fighting for the Nationalists (4,000 Italians, 300 Germans, 1,000 others). The International Brigades suffered heavy losses during the war. Approximately 4,900 soldiers died fighting for the Republicans (2,000 Germans, 1,000 French, 900 Americans, 500 British and 500 others).

Around 10,000 Spanish people were killed in bombing raids. The vast majority of these were victims of the German Condor Legion.

The economic blockade of Republican controlled areas caused malnutrition in the civilian population. It is believed that this caused the deaths of around 25,000 people. About 3.3 per cent of the Spanish population died during the war with another 7.5 per cent being injured.

After the war it is believed that the government of General Francisco Franco arranged the executions of 100,000 Republican prisoners. It is estimated that another 35,000 Republicans died in concentration camps in the years that followed the war.