Romney, who salvaged the Salt Lake Winter Olympics Organizing Committee, was unopposed in the GOP primary, but there was a spirited race between two candidates to be his running mate.
Going into Tuesday, polls showed state Treasurer Shannon P. O'Brien with a lead over her three rivals for the Democratic gubernatorial nomination -- former Clinton Cabinet Labor Secretary Robert B. Reich, state Senate President Thomas Birmingham and former state Sen. Warren E. Tolman.
If O'Brien wins, she will be the first woman nominated by either party as a gubernatorial candidate. A win in November would make her the first female elected governor in Massachusetts.
Swift initially had said she wanted to run for the post on her own, but gave in to party pressures and stepped aside to give Romney an unchallenged shot at the nomination.
This is Romney's second bid for elective office in Massachusetts. He lost in a close race against U.S. Sen. Edward M. Kennedy in 1994.
The primary races have been the most expensive in state history, with the candidates spending a record $20 million.
Despite the spending, a low voter turnout was expected.
Secretary of State William F. Galvin said he expects fewer than 30 percent of the electorate to turn out. He predicted nearly 700,000 will vote in the Democratic primary, and about 240,000 in the Republican primary.
"There is clearly a lack of excitement," Galvin said.
One race that sparked some excitement over the past couple of months is who will be Romney's running mate as lieutenant governor.
Romney's chosen running mate is former state GOP chairwoman Kerry Healey, who is being challenged by James Rappaport, a former GOP state chairman.