The five plants currently generate 40% of Switzerland`s electricity.
Polls suggest a tight race on the issue, which is being championed by environmentalists.
The Swiss Greens and Social Democrats have been pressing for a vote since the Fukushima disaster in Japan in 2011, arguing that Swiss plants are ageing and unsafe.
Following the incident, Swiss authorities announced plans for a gradual phase out of nuclear energy but did not specify dates.
However, government and industry figures argue a quick exit from nuclear power could raise reliance on fossil fuels instead of renewable energy and possibly lead to power shortages.
Recent opinion polls show the "yes" and "no" camps to be neck-and-neck.
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