To acquire a plenary indulgence it is necessary to perform the work to which the indulgence is attached and to fulfill three conditions:
•Eucharistic Communion, and
•Prayer for the intentions of the Supreme Pontiff, all to be performed within days of each other if not at the same time. It is further required that all attachment to sin, even to venial sin, be absent.
A plenary indulgence is granted if the Rosary is recited in a church, a public oratory, a family group, a religious Community, or pious Association; a partial indulgence is granted in other circumstances.
To receive the plenary indulgence attached to the Rosary, the following norms must be observed:
A. The recitation of five decades only of the Rosary suffices; but the five decades must be recited continuously.
B. The vocal recitation must be accompanied by pious meditation on the mysteries.
C. In public recitation, the mysteries must be announced in the manner customary in the place; for private recitation, however, it suffices if the vocal recitation is accompanied by meditation on the mysteries.
D. For those belonging to the Oriental rites, amongst whom this devotion is not practiced, the Patriarchs can determine some other prayers in honor of the Blessed Virgin Mary (for those of the Byzantine rite, for example, the Hymn “Akathistos” or the Office “Paraclisis”); to the prayers thus determined are accorded the same indulgences as for the Rosary.