They're planning to mark the moment with a special "Thanksgiving" service on Sunday, June 14, featuring music from longtime member and jazz great Oliver Jones.
"We have our place to worship again and it's our home and this is where we've been and this is where we're gonna stay," said Ingrid Dixon, who sings in two choirs at Union United Church.
The church has undergone major repairs, costing approximately $1 million, for the first time since 1958.
Mould and asbestos have been removed and the church now has a new roof, new skylights, new ceilings, new floors, fresh paint and accessible bathrooms.
There are still about 36 doors needing to be painted and some brick work needed outside the church, said Erene Anthony, chair of the board at Union United Church.
"I know the work continues, but at least we've got to the point where we can move back and our members have been extremely anxious to get back here," she said.
'It has not been easy'
It's taken four years primarily because it was so hard to raise the money. Initially the congregation hoped to add a third floor to the building in a plan that would have cost $6 million.
That plan was scaled back when members realized how difficult it was to raise $1 million.
During the renovations, the congregation had been worshipping at Rosedale Queen Mary United Church in NDG, with many items sitting in storage.
They were forced to leave Rosedale by the end of March because it was sold, but Union United's building was not ready.
So the congregation moved again, this time to Wesley United Church in NDG.
"I just thank god for giving me the strength to last this long as we went through this four year process because I know, personally, it has not been easy," Anthony said.
One challenge was keeping contact with community groups located near Union United's building on Delisle Street, while being located in NDG.
That was especially tough for outreach director Kaye Francis McKenzie, who is eager to move back.
"We're planning to do things with Atwater Library...Tyndale St Georges (community centre), Little Burgundy Coalition, we've been doing nutrition workshops so I have lots of things, exciting things planned for women, children and families so I'm just happy to get my ideas going," she said.
Nine-year-old Asher Zulu-Hernandez says he remembers singing in the kids' choir when he was five years old and he misses that.
He hopes that choir will start up again after the move back to Delisle Street.
"The choir is actually fun because we sing fun songs," he said.
About 400 families are members at Union United Church and services can draw well over 200 people, Anthony said.
They're hoping to attract a big crowd at their "Thanksgiving" service this coming Sunday.
It will start at 1 pm, so that people from other churches can also attend.
Jones has donated a grand piano to mark Union United's return.
"My first concert was 75 years ago at the church...on a very old piano," he said.
"I always promised that I would buy a new piano for the church so I thought this was a good time to do it."
Jones says he also plans to celebrate by playing a solo at Union United Sunday.
"I think everyone will be excited to be back home," he said.