The atmosphere was electric as more than 3,000 people took part in the traditional parade to mark the national holiday, including 17 international marching bands and 10 theatrical pageants from all over the country.
Marching bands, stilt walkers, Irish dancing cows, giant pigs and cavorting butterflies were the order of the day as over 400,000 people turned out in the capital alone to commemorate the national saint.
Four of Ireland's international aid agencies took pride of place at this year's parade as grand marshals in recognition of Irish generosity towards the people affected by the Asian tsunami.
The aid agencies Concern, GOAL, Irish Red Cross and Trócaire rolled along at a stately pace as colourful mayhem was unleashed behind them.
A street theatre pageant erupted on to the streets, taking the parade off to a lively start as they wielded batons and beat out a rhythm on metal bins.
The Clondalkin Youth Band from Dublin brought some order to the parade, shortly followed by the Roosevelt Roughriders Band from Seattle in Washington, dressed in the colours of the Irish flag.
They were followed by colourful winged creatures and stilt walkers battling against the gusts of wind to keep their precarious perch.
The children in the crowd shrieked with delight as Bui Bolg Productions from Co Wexford took to the streets. The giant puppet outfits with strange faces were a big hit, as were the Irish dancing cows, giant sheep and huge purple and pink butterfly.
The 3,000 people taking part in the parade came from all over the world with the youngest participant aged seven years old and the oldest 81.
The parade broke with tradition and started on the north side of the city this year to mark a decade since the St Patrick's Festival committee began organising and improving the drama-filled show.
Mark Cushen, from the Navan Road in Dublin, who brought his four-year-old daughter Clara to see the parade, said: "It was very good, really colourful, a brilliant show. We come in every year, and it is great that it is starting on the north side of the city for a change."
Like many parents, he held up his daughter on his shoulders for a glimpse of the passing parade.
Clara, whose face was painted with little green shamrocks and flags, said: "I am very excited about it."
Willie Deery from Ashbourne in Co Meath was an expert parade watcher the entire family came equipped with ladders.
"We come in every year, it is a family event," he said, adding: "The parade has improved greatly over the years."
Another festival-goer, Dan Rootham from Bath, England, who was enjoying the parade for the first time, said: "It is a great day for children, as they are the only ones getting the view sitting up on shoulders.
"There is a great atmosphere, and I have met a lovely family standing here. We took turns hoisting up the children."
Further along the parade route on O'Connell Street, Susan Lynch, from New York, whose great-grandparents come from Co Clare, was in Dublin for the second year in a row to celebrate St Patrick's Day.
The 25-year-old said: "I loved it the first time but this time it was even better. People were so friendly I wouldn't miss it for the world, so colourful and vibrant.
"We have our own parade on Fifth Avenue but this tops it. It is just great to be here. It's almost a Mardi Gras atmosphere."
Crowds many waving flags and wearing green lined the streets along the entire parade route from Parnell Square on the north side of the city, along O'Connell Street and on towards Christchurch Cathedral.
Parade watchers were packed into shop windows and on stepladders. Even the base of the Daniel O'Connell monument in O'Connell Street was a perch for people seeking a good vantage point.