Despite the general ban of servile works on feast days, in Spain, as in other Catholic countries, Sundays and holy days of obli-gation did not mean the complete cessation of labour. The synodal statutes show the problematic balance that Catholic theology tried to achieve between the observance of Sunday rest and the maintenance of some economic activities. This paper analyses the causes that legitimate work on feast days. The regulations concerning holy days are more permissive for agricultural tasks and trade transactions than in the rest of activities.