Hundreds of marijuana plants and several weapons were discovered after a fire safety inspection in Whitchurch-Stouffville.
York Regional Police and fire officials conducted the inspection at an address on Innovator Avenue on Friday.
During the inspection, investigators say they found signs of a marijuana grow-op. Officers then arrested a man and a woman who were at the building.
A search warrant was then executed, which led officers to 700 marijuana plants, four rifles, a handgun and a box of ammunition.
The two Markham residents have now been charged with drug and weapon offences.
Both of the accused are set to appear in court at a future date.