The poll, conducted by Democratic firm Public Policy Polling for the League of Conservation Voters, gives Markey the support of 43 percent of likely Democratic primary voters, with Lynch taking 28 percent support.
The League of Conservation Voters has endorsed Markey in his bid to fill the Senate seat formerly held by Secretary of State John Kerry (D).
Markey's lead in this new poll is substantial, but it has diminished somewhat since the last PPP poll, in late January. That poll gave him 52 percent support to Lynch's 19 percent support among Democratic primary voters.
And an equal percentage of Democratic primary voters, 29 percent, said they were undecided in both the January poll and the newest poll. That indicates Lynch's increase in the polls could be due to a funneling of support from Markey.
The Democratic primary to replace Kerry after he joined the administration's Cabinet has barely gotten started, and the candidates have largely focused their efforts on shoring up their own support, rather than targeting each other.
And though Markey still has a substantial lead, and remains strong in terms of both support and finances, this poll is an early indication that Lynch has an opportunity to increase support in the coming months prior to the April 30 election.
The poll was conducted among 426 likely Democratic primary voters from Feb. 13-14 and has a margin of error of 4.8 percentage points.