The singing superstar dressed in black to mourn her pal as she headed to the ceremony in a respectable knee-length frock with small polka dots.
Interior designer to the stars David passed away on 17 July - just three weeks after he was given a skin cancer diagnosis.
In mourning: Madonna looks sombre as she attends her best friend David Collins' funeral in Dublin on Tuesday morning
Madonna, 54, was reportedly devastated when she heard the news.
She jetted into Ireland earlier this week and was present at the funeral on Tuesday morning, alongside around 120 other mourners, including TV presenter Graham Norton.
After the service, Madonna walked to the parish centre clutching a bouquet of pink flowers and a pamphlet. She was joined by David's mother, Helen Collins.
Paying her respects: The Material Girl carried a bouquet of flowers as she walked along the streets dressed all in black
Saying goodbye: She wore a black knee-length frock for the occasion as she joined the rest of the mourners
David was buried in Shanganagh Cemetery in Shankill and his relatives later invited guests to the Ritz Hotel in Enniskerry for a reception to send him off.
After hearing the sad news Madonna posted a picture of some red roses on her Instagram account, writing in tribute: 'In memory of David Collins. He was a great talent and a good and loyal friend for 17 years! God bless him and may he RIP.'
She then flew to England shortly after his death wearing all black.
Sad times: Graham Norton was also at the funeral on Tuesday along with around 120 other guests
Blending in: She remained understated throughout the ceremony to pay her respects
A source told The Sun last week: 'David was one of her closest pals for years - she adored him.
'They’d often have a laugh around London, driving around together. She can’t believe he died just three weeks after his diagnosis.'
On Tuesday she looked sombre as she walked along the streets to the ceremony wearing black shoes and a cross necklace.
Close: Madonna has been friends with interior
designer David for 17 years and paid tribute to him on her Instagram
page when he passed away