Only 17% of voters approve of the plan and 26% are undecided. The question -- "There is a Republican health care plan to replace Obamacare, known as the American Health Care Act. Do you approve or disapprove of this Republican health care plan?" -- did not go into specifics of the plan.
"Replacing Obamacare will come with a price for elected representatives who vote to scrap it, say many Americans, who clearly feel their health is in peril under the Republican alternative," said Tim Malloy, assistant director of the poll.
Most voters, 61%, also disapprove of the way President Donald Trump is handling health care.
One out of every seven Americans -- 14% -- believes they will lose their health insurance under the Republicans' replacement plan.
And the plan doesn't enjoy majority support among Republicans, with only 41% backing the bill.
Nearly half of voters, or 46%, say they will be less likely to vote for their US senator or representative if he or she votes to replace Obamacare with the Republican health care plan.
Nearly one in five say they will be more likely to vote for their lawmaker if he or she supports the replacement plan. And 29% said they vote won't matter.
Most men, 56%, disapprove of the plan as do most women, also 56%. While more than half of white voters disapprove of the plan, even more non-white voters -- 64% -- disapprove.
Overall, 58% of independent voters disapprove of the replacement plan.
Quinnipiac University surveyed 1,056 voters nationwide from March 16 to 21. The poll has a margin of error of +/- 3 percentage points. Live interviewers called landlines and cell phones.