A katavasia (pl. katavasiae, from the Greek katabaino, "go down") is the concluding hymn of an ode of a canon. The most commonly used katavasiae are taken from the irmoi of the canons of feast days. The one used on most Sundays of the year is taken from the canon of the service for the Akathist hymn, which is appointed for the fifth Saturday of Great Lent. On Sundays and feasts, there is a katavasia at the end of each ode, but in normal weekday services, there are only katavasiae at the end of the third, sixth, eighth, and ninth odes.
The katavasia takes its name from the practice of the choir coming down from the kliroi on either side of the church and singing this hymn in the center of the church. This practice is still observed in some monasteries.
In some parishes, for many canons, only the katavasiae will be sung rather than the full text of each ode. In such cases, the interpolated Little Litanies normally included in the canon are omitted, and the katavasiae are sung through without stopping.