It is the third time in just four days that thieves have targeted a church in the Lothians.
In the latest theft, raiders smashed a glass door at St John's Church in Mid Street, Bathgate, on Saturday night or Sunday morning and made off with a haul valued at approximately 4,000.
It happened just a day after thieves took two Victorian lamps from the grounds of St Cuthbert's Episcopal Church in Colinton, and on Wednesday or Thursday last week a set of 50-year-old silver communion cups and plates were stolen from Hopehall Evangelical Church in Broxburn.
Reverend Duncan Shaw said the greatest loss from the St John's robbery was the silver bowl, which has been used at every baptism in the church since it opened in 1895. Eight silver communion plates were also taken.
He said: "As a congregation we're sorry that people should stoop to this level of stealing other people's property, but we're particularly saddened by the loss of the 1895 baptismal bowl and by eight more modern bread plates for use at communion. We simply hope that in time these items might be recovered."
He explained that he had been in the church hall until 10.30pm on Saturday night and locked up as usual when he left: "It was discovered at around half past eight by a parishioner who comes in on a Sunday morning to tidy up for folk arriving.
"He discovered that the glass door had been broken and obviously the church had been entered."
The thieves also ransacked a desk in the vestry and a filing cabinet.
Mr Shaw said: "They managed to enter the safe and took the baptismal bowl. It had an inscription of "Suffer The Little Children", and an inscription to the person who donated it to the church.
"Everyone who has been baptised in this church since it opened has been baptised with water from the bowl and that's the sentimental aspect of it."
The communion plates, which were in a distinctive bag, are about 20 years old.
Police are appealing for witnesses to the theft, and they said there is currently no evidence to link the three recent incidents, although enquiries are ongoing.
A police spokesman said: "This will have been a bitter blow to everyone involved with St John's. Although the items taken are valued at around 4,000, their historic and sentimental value is far greater."