Cannabis worth £110,000 was seized after a fire broke out at a former hotel, authorities said.
Emergency services were called at 04:50 GMT on Sunday to reports of a fire at the former Balmoral Hotel on Fort Terrace in Bridlington.
The property was derelict and no one was believed to be injured, Humberside Fire and Rescue said.
Investigators said the fire, which was ruled as accidental, started from a brazier – used to burn charcoal or other solid fuel – inside the property where someone was trying to keep warm.
Four fire engines and an aerial ladder platform attended, with crews leaving the scene at 09:30.
Officers later found 198 cannabis plants, Humberside Police said.
The 34-bedroom town centre hotel closed in 2019.