The president said that while "we can never repay our debt to theses officers and their families," he hoped his attendance at the event, now in its 32nd year, would signal his appreciation for the sacrifices they made.
"As difficult as times may be, as tough as the losses may be, your mission does not stop," Obama said. "You never let down your guard, and those of us you protect should not let our gratitude slide, either."
Flags across the country will be flown at half-staff on Wednesday in honor of Peace Officers Memorial Day.
Obama was joined at the ceremony by congressional leaders, including House Speaker John Boehner (R-Ohio) and Minority Leader Nancy Pelosi (D-Calif.), as well as administration officials like Homeland Security Secretary Janet Napolitano. Before his remarks, Obama stood next to Attorney General Eric Holder, who is set to testify later Wednesday before the House Judiciary Committee about the Justice Department's subpoena of journalist phone records.
On Tuesday, Holder also announced that he would open an investigation into the IRS's targeting of conservative political groups.