About 120 officers executed raids targeting a drug trafficking ring in Saint-Amable, east of Montreal.
So far 12 people have been arrested on suspicion of trafficking cocaine, methamphetamines, hashish and marijuana.
Quebec provincial police Sgt. Ingrid Asselin said the police operation began at 5:15 a.m.
Investigators carried out nine search warrants at homes and four search warrants at vehicles.
Asselin said she expects more arrests throughout the day.
Provincial police, along with officers from the Montreal, Longueuil, Richelieu-Saint-Laurent and Saint-Jean-sur-Richelieu forces are involved.
A second police operation targeted a suspected methamphetamine trafficking ring in the Montmagny region, east of Quebec City.
A team of about 40 officers arrested six people and searched five homes.
The Montmagny raids are part of a provincial investigation that began in January.