A teenage girl was among three people arrested after police seized £250,000 of heroin, cocaine and cannabis.
Renfrewshire and Inverclyde Serious and Organised Crime Team executed search warrants at five addresses in Greenock in the early hours of Tuesday.
At two of the properties they found the drugs as well as a five-figure sum of cash.
A 16-year-old girl was arrested with a 31-year-old woman and a 56-year-old man.
Smaller amounts of drugs were seized in two of the other properties and two men, aged 38 and 60, will be the subject of a report to the procurator fiscal.
Chief Inspector Paul Cameron, the Area Commander, said: “This has been a very successful operation which highlights our dedication to tackling drugs activity within the Greenock area.
“Drugs can have a devastating impact on communities and local officers work alongside specialist teams on a daily basis to deter and detect this type of criminality.
“I hope today’s outcome sends a clear message that drugs have no place here and Police Scotland will continue to use all resources at its disposal to combat this issue.”
Detective Inspector Robert Bowie, from the Serious and Organised Crime Team, said: “A significant quantity of controlled drugs has been taken off the streets as a result of this pre-planned, intelligence-led operation to tackle serious and organised crime.
“I would like to take this opportunity to thank the local community for engaging with us throughout this operation.
“Their support has been absolutely vital and I would continue to encourage anyone with concerns about drugs activity in their area to pass this information on to the police.”