Two staffers from Radel's Washington, D.C. office left in November 2013 to take positions with Endeavor Strategic Communications. Endeavor, the public relations and communications firm founded by former Darrell Issa aide Kurt Bardella, Radel's communications director and former digital director.

Radel was arrested in the District of Columbia on October 29, 2013, for possession of cocaine. He was then charged on November 19, 2013, in D.C. Superior Court with misdemeanor possession of cocaine. He appeared in court on November 20, 2013. The charge carried a statutory maximum of six months in prison and a fine of $1,000. House Speaker John Boehner commented on the incident, "Members of Congress should be held to the highest standards, and the alleged crime will be handled by the courts. Beyond that, this is between Rep. Radel, his family, and his constituents." Sentencing Radel pleaded guilty on November 20, 2013, to misdemeanor cocaine possession. According to court reports, Radel bought $260 worth of cocaine from an undercover Drug Enforcement Administration agent in October 2013. He was sentenced to one year of supervised probation and fined $250. Radel also announced plans to enter an in-patient rehab program in Florida. Substance abuse rehabilitation Radel announced on November 20, 2013, a leave of absence in order to enter a substance abuse treatment facility in Florida. He also said he would donate his congressional salary to charity during his leave. On December 19, 2013, Radel left rehab, where he was seeking treatment for his alcohol addiction. He did not discuss future political plans and added, "Politics and re-election are the last thing on my mind right now." Ethics investigation The House Ethics Committee announced on December 16, 2013, the launch of a formal investigation into alleged misconduct by Radel. Radel apologized On January 8, 2014, after returning to Washington D.C., Radel apologized to House Republicans for his cocaine bust, saying that the episode helped bring him closer to his wife and child. Republican response Greg Walden, chair of the National Republican Congressional Committee, initially said he would refrain from comment on whether Radel should resign until he hears what he has to say about the incident. Walden said on November 20, 2013, that he had not talked to Radel since he pleaded guilty to a misdemeanor charge of cocaine possession. He also said that “he’s going to need to explain what happened, and then make some decisions.” Lenny Curry, the chairman of the Republican Party of Florida, asked Radel to step down on November 25, 2013. Curry released a statement saying, "The people of Florida’s 19th Congressional District need a Congressman who is 100 percent focused on the needs of Southwest Florida. Therefore, Congressman Radel should step down and focus his attention on rehabilitation and his family.” Terry Miller, Lee County GOP chair, and Mike Lyster, the chairman of the Collier County Republicans, issued identical statements on November 25, 2013, that Radel should step down. They also added if he runs for re-election in 2014, Radel “would not enjoy our support." “While the decision to complete the current term is his alone to make, we strongly encourage him to reflect on his ability to remain effective and that a return to Congress may serve only as an impediment to his recovery,” the pair said in separate statements. “We feel it is in the best interests of all involved that he resign immediately. We hope that he can focus solely on his rehabilitation and allow the citizens to begin their own healing process. We thank Trey for his service and wish only the best for him and his family.” Speaker John Boehner, House Majority Leader Eric Cantor and Majority Whip Kevin McCarthy have not said that Radel should resign, but rather that it is up to Radel, his family and constituents. John Boehner commented on the incident, "Members of Congress should be held to the highest standards, and the alleged crime will be handled by the courts. Beyond that, this is between Rep. Radel, his family, and his constituents." Governor Rick Scott (R) Scott called for Radel to resign on November 26, 2013. In a statement he said, "I agree with the party chairman. Look, Trey's going through some hard times. My prayers and my wife's prayers are with his family, but we have to hold all of our elected officials to the highest standard." Pam Bondi, Florida Attorney General “As a career prosecutor, I understand the devastating effects that addiction can have on one’s life,” Bondi said on November 27, 2013. “While I understand that this is a challenging time for Trey and his family, I believe that he should resign.” The Southwest Florida Young Republicans (SWFL Young Republicans) The group voted on December 2, 2013, to support Radel's decision to stay in the post, despite pressure to step down. The group also approved a statement, but took no position on whether Radel should seek re-election in 2014. The group issued the following statement: “Last night, the SWFL Young Republicans met to have an open and honest discussion regarding Congressman Trey Radel. We believed that it was important for our members, many of which are new to the political process, to be able to voice their opinion on whether our congressman should be encouraged to remain in office through the remainder of his term or resign. Following our discussion, a vote of our membership was held. The resulting vote was that sixty percent of our members supported Congressman Radel remaining in office for the balance of his term. Our members took no action on re-election, but solely on completing the current term of office. Our members believed that the restrictions placed on constituent services combined with the lack of voting representation that would be created by a congressional vacancy would place Southwest Florida and the Republican Party at a severe disadvantage. A special election would be costly and take 4-6 months. Our district would then face another election shortly thereafter. Based upon this realistic assessment of the situation, we chose to support continued representation at the Congressional level . Although we do not condone Congressman Radel’s actions, we do not believe that the constituents of our district should lose representation due to those actions.” Newt Gingrich compared Radel to Anthony Weiner, and indicated that while Radel's constituents could forgive him in time, he cautioned about a relapse. “I think the burden is on him to prove that he [has] genuinely been rehabilitated. He needs to slow down, focus on rehabilitation and people will be patient...Does he come out of rehab genuinely changed or is it all a gimmick? If it’s a gimmick, he won’t survive. The example we had with Weiner in New York is that people will forgive you once. They won’t forgive you twice.” Democratic response Nancy Pelosi Pelosi did not call for Radel to resign, but on November 21, 2013, she did attempt to link Radel’s behavior to the move by Republicans to cut food stamps and require recipients to get drug tested before receiving benefits. “The inconsistency on the Republican side to say, we’re going to cut $40 billion out of food stamps and by the way you should be drug tested before you can get food stamps, when people are voting to do that are engaged in that activity."