Gore Bay OPP are investigating after three men went through the ice near Gore Bay on Manitoulin Island.
The incident happened around 8 AM on Friday when their ATV broke thru the ice on Lake Wosley.
Two of the men riding in the ATV were able to rescue themselves.
A third rider, a 55 year old man from Sudbury, is still missing, and the ATV is completely submerged.
Gore Bay OPP are on site investigating, and the OPP Underwater Search and Rescue Unit has been called in to help.
The OPP reminds recreational fishermen and ATV and snowmobile operators that this is the 2nd recent event where a person has gone through the ice on Lake Wosley.
Earlier this week, a snowmobile operator went through the ice on the same body of water with his snowmobile but was able to make it to shore safely.
The OPP strongly urges extreme caution when venturing out onto area waterways as ice conditions have proven to be highly unpredictable.