Some £1,000 raised for the Royal British Legion was stolen from St Andrew's Church, Backwell after thieves smashed down the door of the rectory and stole keys to access the main church building before breaking into the safe.
Donations were made by more than 300 members of the congregation at a Remembrance service last Sunday.
Rev Dr Katy Garner, who was licensed as Rector for St Andrew's in July, said she was "sickened" by the news in a statement on the Dioceses Facebook page: "I sat on Sunday in the services alongside a disabled veteran from World War II and the thought that anyone could take money from these men and women and the thousands who are helped by the Royal British Legion is just sickening.
"We are all deeply upset."
The doors of the rectory and the church office sustained considerable damage but the main 16th century building was not affected.
Police are investigating the incident, dusting for fingerprints and carrying out a search of the area.
A special service will be held in the church next Sunday morning to take up a second collection for the Royal British Legion.
An online fundraising campaign has also been launched to help recoup the stolen funds.
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