"I have sung many times in his casinos, but I won't do it again. He seems to be an asshole," he told Barcelona-based daily newspaper La Vanguardia in an interview on Wednesday.
"He thinks he can fix the world forgetting what immigrants have done for his country. He is a clown! And my apologies to clowns."
Real estate mogul and Republican presidential candidate Trump said in a speech June 16th that some Mexican immigrants bring drugs and crime to the United States, and some are rapists. He has also called for the mass deportation of illegal immigrants.
Various organizations have severed their ties with Trump over the comments, including Spanish-American celebrity chef Jose Andres who backed out of plans to open a flagship restaurant in a new hotel under construction by the mogul.
Trump's inflammatory rhetoric has alienated Latino voters. He is viewed unfavourably by 82 percent of Hispanics, with just 15 percent viewing him favourably, according to a Washington Post/ABC News poll released last month.
Famous for his romantic ballads and love life that has garnered tabloid headlines, Iglesias, 72, is Latin music's top-selling artist, with 300 million albums sold in his decades-long career.
His latest album "Mexico" features 12 songs with a Mexican flavour and pays tribute to the country's great songwriters.