Prime Minister Mariano Rajoy's conservative Popular Party, which has pushed through painful spending cuts to reduce the public deficit, has a narrow lead over the main opposition Socialists, the poll showed.
Over 64 percent of those polled said they would "certainly" or "probably" vote, against over 24 percent who said they would certainly or probably not vote, according to the survey by the Centre for Sociological Studies. The rest were undecided or did not answer.
The Popular Party would capture almost 34 percent of the vote, giving it 20 or 21 lawmakers in the European Parliament, while the Socialists have 31 percent support, giving them 18 or 19 seats.
The poll also found that 58 percent of all Spaniards had a "favourable" or "very favourable" impression of the European Union.
Over four in 10 people, 43 percent, felt Spain's entry into the European Union in 1986 had "mainly benefited" the country against 30 percent who felt it had "mostly suffered" from membership.
Voters from across the 28-member European Union will go to the polls between May 22nd and May 25th to decide the 751 deputies who will sit in the European Parliament from 2014-2019. Spain votes on May 25th.
During the last European elections voter turnout in Spain was 44.9 percent, slightly higher than the 43 percent average for the entire European Union.
The survey of 4,737 eligible voters was carried out April 7–26 and it has a margin of error of 1.5 percent.