<page_title> List of undefeated boxing world champions </page_title> <table> <cell> United States Floyd Mayweather Jr. <col_header> Boxer </col_header> </cell> <cell> Super featherweight <col_header> Weight class </col_header> </cell> <cell> Lightweight <col_header> Boxer </col_header> </cell> <cell> Light welterweight <col_header> Boxer </col_header> </cell> <cell> Welterweight <col_header> Boxer </col_header> </cell> <cell> Retired at 49–0 in 2015; returned in 2017 for non-title McGregor fight and then retired again. <col_header> Championship years </col_header> </cell> <cell> Light middleweight <col_header> Boxer </col_header> </cell> </table>
In Floyd Mayweather Jr.'s career, he held multiple world titles in five weight classes (twice at welterweight) and retired with an undefeated record.