This may seem like an unusual question, but just how long is a rosary? How many prayers does it take to pray the rosary? The Short Answer The rosary consists of fifteen mysteries, three sets of five each: the Joyful, the Sorrowful, and the Glorious. For each mystery, also referred to as a “decade”, one prays one Our Father, ten Hail Marys, and a Glory Be, meditating on that mystery throughout.