Some 25,000 pilgrims have part in the Reek Sunday pilgrimage on Croagh Patrick in Co Mayo.
A climber was earlier removed to hospital after suffering a suspected heart attack.
The Mayo mountain is over 700m high, and many did the climb in their bare feet.
Mass was be celebrated in the chapel at the summit by Archbishop Charles J Brown.
The Order of Malta has 120 volunteers on-hand to provide support.
The Mayo Mountain Rescue Team noted that already this year, their number of call outs have increased by 30% on the same period last year - with the majority being on the mountain.
Lieutenant Eamon Berry, spokesperson from Order of Malta, said earlier: "Extreme caution is urged upon all climbers given the dangers posed by the climb."
"The Order of Malta are stressing the importance that climbers are suitably equipped for all weather, regardless of ground conditions."
"It is imperative that suitable footwear be worn, along with warm clothes and rain gear, as well as sun protection."
"All climbers should also bring a plentiful supply of water and snacks, while extra care must be taken with children on the mountain."
The annual Croagh Patrick pilgrimage has been carried out for over 1,500 years.
But last year the official pilgrimage was cancelled due to extreme weather conditions.