2020 Colorado Senate election

[1] Voters in 18 out of 35 districts of the state Senate elected their representative for a four-year term.

In the previous state Senate election (2018), the Democrats claimed control of the chamber from the Republicans, gaining two Republican seats and one independent (formerly Democratic senator) seat.

Therefore, for Democrats to have lost their absolute majority in the Senate in this election, Republicans and other parties would have needed to gain at least two more seats.

One Democratic and three Republican incumbents are term-limited and prohibited from seeking a consecutive third term.

[2] Bold - Gain Italics - Hold, new member Seats where the margin of victory was under 10%: District 4 • 8 • 10 • 12 • 14 • 17 • 18 • 19 • 21 • 23 • 25 • 26 • 27 • 28 • 29 • 31 • 33 • 35