Membership peaked in 1964 at 1.1 million and has declined since that time. From 1991 to 2001, the number of people claiming an affiliation with the United Church decreased by 8%, the third largest decrease in mainstream Christian denominations in Canada. In 2011, Statistics Canada reported approximately 2 million people identifying as adherents. The 2021 Canadian census found that more than 1 million Canadians (3.3% of the population) self-identified with the church, remaining the second-largest Christian denomination in Canada. Church statistics for the end of 2018 showed 388,363 members in 317,051 households under pastoral care, of whom 120,986 attend services regularly in 2,119 communities of faith representing 2,774 congregations.
The United Church has a "council-based" structure, where each council (congregational, regional, or denominational) has specific responsibilities. In some areas, each of these councils has sole authority, while in others, approval of other councils is required before action is taken. (For example, a congregation requires regional council approval before a minister can be called or appointed to the congregation.) The policies of the church are inclusive and liberal: there are no restrictions of gender, sexual orientation or marital status for a person considering entering the ministry; interfaith marriages are recognized; communion is offered to all Christian adults and children, regardless of denomination or age.