Pelosi, D-Calif., underwent "a few tests" at the hospital, Rep. Bill Pascrell, D-N.J., traveling with Pelosi, told NBC News Monday.
"She's at the hotel now," Pascrell said. "She's fine, she's in good shape. Just a few tests to make sure she was all right."
Doctors at the hospital emergency room did not specify her illness.
"We conducted some tests to determine the state of her health," said Dr. Claudio Modini of the Umberto I Polyclinic hospital in Rome
A bipartisan delegation, including Pelosi and Pascrell, had spent time in Afghanistan before traveling to Italy.
"We had a strenuous few days in Afghanistan, but it was the most productive trip I've ever been on as a member of Congress," Pascrell said.
Pelosi, who turns 71 Saturday, was scheduled to meet with Italian Defense Minister Ignazio La Russa and lower house of Parliament Speaker Gianfranco Fini, Adnkronos International reported.
She is visiting Italy to commemorate its 150th anniversary as a unified country, it reported.