As of press time, the Republicans won 20 Senate seats, while Democrats received 26 spots -- allowing the party to keep control of the 50-seat chamber.
With these additions, Republican representation in the Senate will jump from 15 to at least 22 seats.
The increase in Republican winners can be at least partially attributed to newly drawn districts that some Democrats said favored the Republicans.
Republican officials were successful earlier in the year at overturning Democratic-drawn district maps that some said would unfairly favor the Democrats.
Democratic candidates won 58 seats in the House as of press time. Republicans won 57. Five seats were undecided, leaving control of the chamber still in doubt early Wednesday.
The majority in the Senate favors Democrats 35-15, while in the House the split is a tight 62-58.
Democrats have controlled the Senate for more than a century.
Incumbents who were locked in close contests based on early returns include Sen. Fountain Odom, D-Mecklenburg, one of the legislature's most influential members. Sen. Eric Reeves, D-Wake, was beating former Raleigh Mayor Paul Coble by fewer than 500 votes with 59 of 60 precincts counted.
Republicans also won both N.C. Supreme Court seats that were available and at least four of five races for the N.C. Court of Appeals.
