On 30 November 1939, Russian troops invaded Finland, thus beginning the Winter War - a war which has been viewed as a question of the 'fate of the Finnish nation'. Only some 20 years had passed since independence in 1917 and since the bloody Civil War between Reds and Whites in 1918. As a consequence of the latter, major cleavages in Finnish society remained up until the final years of the 1930s. Equality in sacrifice was a highly sensitive question. It can be assumed that the greater the differential in casualty rates between soldiers from different social backgrounds, the worse the combat morale. This study compares the social backgrounds of those who were killed in the Winter War with those who survived. We find an uneven distribution of victims by socio-economic group, with considerable differences. Casualties were disproportionately high among unskilled workers from the countryside, indicating that people with the same social background as the Reds in the Civil War suffered most from the Winter War. If equality in sacrifice was so important, then we can assume this to have strongly influenced political opinion after the war. After the Winter War, the Communist Party was forbidden in Finland; however, Communist support remained strong. Inequality of sacrifice may be one explanation for this.