The poll reveals that the gap between those who want independence and those who don't is widening and if a referendum on Catalan independence took place, the "no" vote would be 50 percent while the "yes" vote would be 42.9 percent.
The study was carried out by the Centre d'Estudis d'Opinió (CEO), Catalonia's opinion polling office and will be unpleasant reading for pro-independence supporters, including President of the regional government of Catalonia, Artur Mas.
The latest poll shows an increase in the percentage of Catalans who would vote “no” to independence; in the previous poll, published in March 2015, the "no" vote was at 48 percent while the "yes" vote was 44.1 percent.
The survey also shows voter intentions in the upcoming Catalan regional elections. The pro-independence CiU-ERC would win the most votes, with 13.3 percent, followed by Podemos, the left-wing protest party that is barely more than a year old, with 10.8 percent.
Catalonia is home to 7.5 million people and accounts for a fifth of Spain's economy.
Proud of their distinct language and culture, many Catalans, including the region's conservative leader, Artur Mas, want to create a new state in Europe in defiance of the Spanish government.
But support is continuing to wane; in June three ministers from the junior party in the coalition that runs Catalonia pulled out of the regional government due to disagreements over its push to break away from Spain.
And the rise of Podemos, a protest-party that grew out of the Indignados (the Outraged) movement, is also blowing independence plans off course.
Barcelona recently voted in its first woman mayor, left-wing candidate Ada Colau who replaced staunchly pro-independent Xavier Trias
She ran for office at the head of Barcelona En Comu (Barcelona In Common), an alliance of grassroots groups including members of the left-wing party Podemos.