Burglars broke into the Plough Pub on Newark Road in Lincoln and stole cash from a gaming machine.
The incident happened at around 1.30am on Monday, June 17.
The offenders gained entry to the pub by smashing a security door window with a paving slab taken from the patio.
They then forced open a gaming machine with a crowbar and stole cash from the machine, Lincolnshire Police said in a statement.
It is believed two men wearing hoods were responsible and they fled along the path that runs alongside the river next to the pub in the direction of Boultham Park.
Anyone with any information about this offence is asked to contact PC Paul Mayo of Lincoln via the non emergency 101 number.