"We are pleased to announce an end to the work stoppage which commenced Nov. 22," said Glenn Rice, president of UPS Canada.
"We apologize to our customers for any disruptions. With the immediate reinstatement of service, we are working closely with customers to meet their needs."
The usual delivery guarantees will be in effect for all shipments picked up on Wednesday, the company said.
After five months of talks, the Canadian union leadership and UPS management had previously agreed on a tentative contract. But union members rejected the deal and late last week the Teamsters gave the company a 72-hour notification of a work stoppage.
UPS ships an average of about 13.6 million packages a day on its planes and trucks.