The finale of the Heineken Green Energy Festival takes place today with an all-day event in Dublin Castle starting at 3 p.m.
The festival, which started last Thursday night, is expected to have been attended by more than 20,000 people by tonight.
Festival highlights included two sold-out performances in the Olympia Theatre by Irish music legend Van Morrison who played Friday evening and a matinee show on Saturday afternoon.
Some 4,500 people were in the courtyard of Dublin Castle last night to see acts like Muse and the Hives. Security was tight with all bags searched on entry and ID was required for anyone wishing to purchase alcohol. According to a security spokesman, there were "spotters" in the crowd on the lookout for underage drinkers and the distribution of drugs.
Some 150,000 pints of beer were bought at last year's Green Energy festival. A senior medical spokesman at the event said the vast majority of incidents requiring medical attention this year were drink related.
The Garda Press Office said late yesterday evening that there had been no arrests.
One man was taken to hospital on Saturday night after he was knocked down by a vehicle as he was crossing the road to Dublin Castle from the Olympia on Dame Street.
The festival is in its fifth year and concerts were run in a number of Dublin's leading venues, including the Olympia, Ambassador, the Temple Bar Music Centre and Whelans on Wexford Street.
Interest in the festival has been helped by an extensive promotion campaign and unbroken sunshine since early Saturday. Today's show begins at 3 p.m. and is headlined by The Frames. The Green Energy Festival will be in Cork later in the summer.