Special elections to fill the seats vacated by Rep. Stephen Dargan, and Sens. Eric Coleman and Rob Kane will be held Feb. 28.
All three lawmakers, who won their 2016 re-election campaigns, resigned their seat before taking the oath of office on Jan. 4.
Gov. Dannel P. Malloy filed the writs for the special election Friday.
Up for grabs is control of the state Senate, which is currently evenly divided 17-17. The seat vacated by Coleman, which includes portions of Bloomfield, Hartford, and Windsor and the one vacated by Kane, which includes Bethlehem, Bridgewater, Oxford, Roxbury, Southbury, Washington, Watertown, and Woodbury, and portions of Middlebury and Seymour are thought to be safely Democratic and Republican districts. That means Senate leaders expect the election to result in an 18-18 split.