Unionized nurses at Baystate Franklin Medical Center and Baystate Noble Hospital have voted to reject what they called a "best and final" contract offer from Baystate Health.
The two sides began bargaining in November 2016 and have been working under terms of an expired contract since the beginning of the year.
Baystate Noble Hospital nurses have also voted to authorize a one-day strike, but have not set a date.
Baystate Franklin nurses staged a one-day strike in June and were subsequently locked out for two days.