Firefighters were called to attend a fire in a commercial property on Vale Road, Llandudno Junction on Thursday evening.
The initial call was received at around 7.30pm where five fire appliances from Llandudno, Conwy, Colwyn Bay and Abergele we called into action, together with an aerial ladder platform and incident command unit from Rhyl.
An unknown male was treated at the scene for smoke inhalation and a number of properties neighbouring the location were evacuated as a precautionary measure.
Over 40 firefighters were said to be in attendance tackling the fire which became under control during the early hours but crews remain present whilst damping down.
North Wales Police and North Wales Fire and Rescue Service are working closely together with Scottish Power to return power to the area so that residents who were evacuated as a precaution can return to their properties and so that businesses can get back to normal.
Structural engineers are working to assess the safety of the stricken building.
Police and fire officers will conduct a joint investigation to establish the cause of the fire.