Mr Hall said he would report back to Congress after his four-day trip.
Tony Hall spoke to suffering children and their parents, and met the Iraqi health minister as part of his trip to assess the country's humanitarian situation.
He is one of the first American congressmen to travel to Iraq since the Gulf War in 1991.
Possible help
One father, carrying his sick son in his arms, pleaded with the congressman: "Don't you have a conscience? Don't you have a God? My child is going to die and there's nothing I can do for him."
Mr Hall said he would report back to Congress after his four-day trip.
He told reporters that he wanted to understand why so many children were sick, why food and medicine were not getting through, and what he could do to help.
He also said he wanted to find out if the shortages had any causes other than international sanctions.
After visiting the hospital, Mr Hall went on to a meeting with the health minister, Umid Medhat Mubarak, although he had previously said he did not intend to meet any Iraqi officials.
Ignorance
Mr Hall said that, although 70 congressmen in the US had recently asked Washington to reconsider its policy on Iraq, the majority of Americans were not aware of the situation.
"Most people, especially Americans, are not familiar with the suffering. I think if they knew about it they'd have a different attitude," he told the BBC.
Iraq has said repeatedly that its people are dying in their thousands because of shortages of essential goods and medicines caused by sanctions.
An economic embargo has been in place since 1990, but the 1996 United Nations' oil-for-food programme allows Baghdad to buy food and medicines under strict international controls.
Effectiveness
Mr Hall's delegation will consider whether the mechanism is working effectively.
"If the oil-for-food programme is not working, and we don't have enough workers or goods and services to deal with problems such as dirty water and immunisation, then we must do a better job," he said.
Mr Hall, who arrived on Sunday by road from Jordan, is accompanied by international Red Cross, Red Crescent and United Nations officials.
During his visit, he is also due to meet representatives of relief organisations and visit schools and clinics.