Scottish Labour could slump to third place in Holyrood elections
The Survation findings for the Daily Record forecast the party will win only 21 seats in the 129-member Scottish Parliament, one less than the Tories.
The SNP, meanwhile, are on course for another huge majority with 70 seats.
The poll follows a forecast by the Press Association last week which also said the Tories will beat Labour to second place.
It also comes on the day Scottish Labour's spring conference kicks off in Glasgow.
According to today's Survation poll, the SNP are on an astonishing 54% in the constituency section of the ballot, and 42% in the regional top up list.
By contrast, Labour are on 20% in the constituency section, four points ahead of the Conservatives, while both parties are tied on 18% in the regional list.
A Scottish Labour spokesman said: "We will go into this election with a bold plan to give everybody in Scotland a fair chance in life. We are in no doubt about the scale of challenge but we are confident in our vision for Scotland."
A spokeswoman for the Scottish Conservatives said: "People are responding to Ruth Davidson's pledge to hold the SNP to account.”
SNP business convener Derek Mackay said: “This is yet another very positive poll for the SNP as we approach the election – but is an absolute disaster for Kezia Dugdale on the morning of her own conference.
“People are continuing to reject a chaotic and divided Labour party which isn’t even regarded as a credible party of opposition, never mind a credible party of
government – and which finds itself locked in a desperate battle for second place with the Tories.
“And with their complete lack of any positive vision for Scotland, Labour’s position is only going to get worse."