Sanders made the comments to a crowd gathered at a rally in Philadelphia, where he said Clinton seemed "nervous" over his recent string of primary victories.
"She has been saying lately that she thinks I am quote-unquote 'unqualified' to be president. Well, let me just say in response to Secretary Clinton, I don't believe that she is qualified if she is through her super PAC taking tens of million of dollars in special-interest funds. I don't think that you are qualified if you get $15 million from Wall Street through your super PAC. I don't think you are qualified if you have voted for the disastrous war in Iraq. I don't think you are qualified if you have supported virtually every disastrous trade agreement that has cost us millions of decent-paying jobs. I don't think you are qualified if you supported the Panama Free Trade Agreement, something I very strongly opposed and which all of you know has allowed corporations and wealthy people all over the world to avoid paying their taxes to their countries.
This campaign is gaining momentum because we are listening to the American people, not wealthy campaign contributors."
Sanders appeared to be referencing an interview from earlier in the day on MSNBC's Morning Joe where Clinton was asked three times if she thought Sanders was qualified to be president. She said voters would have to make that decision.
Host Joe Scarborough asked the questions in light of a recent interview Sanders conducted with the New York Daily News where the candidate was pressed on how he would break up big banks, a frequent promise of his campaign. The newspaper asked Sanders if he believed the Federal Reserve already has the authority to take action.
"Well, I don't know if the Fed has it. But I think the administration can have it," Sanders replied.
Scarborough asked if Clinton thought Sanders was ready and qualified to be president.
Clinton said it seemed that Sanders hadn't "done his homework," which raised questions.
"What he has been saying about the core issue in his whole campaign doesn't seem to be rooted in an understanding of either the law, or the practical ways you get something done." she said. "And I will leave it to voters to decide who can do the job that the country needs."