The number of people looking for a job in Windsor and London jumped by 0.7% last month.
Statistics Canada's Labour Market Survey shows Windsor's jobless rate now stands at 9.7%, up from 9% a month earlier.
Windsor's rate is 1% higher than any other city in the country, with Montreal next closest at 8.7%.
London's rate also increased last month, now sitting at 7.3%. That is up from 6.6% in August.
Nationally, the economy added 12,000 jobs in September, but the unemployment rate climbed by one-tenth of a percentage point to 7.1% as more people entered the labour force.
