Support for Scottish independence has gone up to 36%, a rise of 4% since March, a new poll by Ipsos MORI for STV suggests.
The percentage of those intending to vote No fell three points to 54%, while 10% of those questioned were still undecided, down one percentage point from the last poll.
When undecided voters are removed from the figures, 40% of those certain to vote said they would vote Yes while 60% would vote No.
The poll shows that 46% of men intend to vote Yes in September, while only 28% of women support independence.
The level of public interest in the referendum appears to be growing, with more than eight in ten (82%) saying they are certain to vote, up four percentage points from the last poll.