Municipal workers discovered the theft on Monday after noticing two of the chapel's door locks had been broken.
When they checked the Virgen de Sacedón and Christ Child carvings, they noticed both were missing their gold crowns.
The holy sculptures have been the emblem of Pedrajas de San Esteban in Castilla – La Mancha since the village's pilgrimage began to take place in the 17th century.
Pedrajas de San Esteban's mayor Sergio Ledo told Spanish news agency Europa Press he was disgusted by the robbery, especially considering it occurred the night before the village's most important celebration.
"Even though the crowns aren't very expensive, their theft is a huge insult to the villagers and their heritage."
Ledo told Europa Press that "fortunately" the chapel has a spare silver crown to replace the golden one.
Spanish Guardia Civil believes the thieves managed to break in by using a signal jammer or that the chapel's alarm was simply not working.
The Virgen de Sacedón celebrations will continue as planned on Monday afternoon with locals and outsiders taking part.