The infection occurred in a man from the Regina Qu'Appelle Health Region who experienced no symptoms.
It was detected by Canadian Blood Services in screening before the person was to donate blood.
Officials are urging people to take precautions against mosquitoes in light of the recent hot, humid weather which has created ideal conditions for their development.
Dr. Saqib Shahab (shah-KEEB' shah-HAB'), the province's chief medical health officer, says it's part of a trend throughout the continent.
"This year we are seeing a pattern throughout Canada and North America, where there is an increase of positive mosquito pools as well as cases," he said Friday.
"What's happened this year is a bit different from what happened the last two years," he said. "The last two years we had no cases and we had no positive mosquito pools as well. And that was for a variety of ecological and climatic reasons. Cold winters, cool springs and cool summers."
Most people infected with West Nile will experience no symptoms or only mild illness such as fever, headaches and body aches.
Shahab explained that the Culix tarsalis mosquito that carries the virus primarily comes out at dusk and dawn, although may be about during the day when it's cloudy and cooler.
"It's called an ankle biter, because it will bite you around the ankles," he said. "You may not even hear it buzzing around your head."
The worst year for West Nile in Saskatchewan was 2007 when more than 1,400 human cases were reported and the virus contributed to six deaths.
Two people in Winnipeg were also confirmed to be carrying the virus earlier this week. It so detected in routine screenings by Canadian Blood Services.