The latest funding by Washington is intended to support Ukraine through September, and it dwarfs an earlier emergency measure that provided $13.6 billion.
US President Biden has signed legislation to support Ukraine with another $40 billion in military and economic assistance.
The legislation, which was passed by Congress with bipartisan support, deepens the US commitment to Ukraine at a time of uncertainty about the conflict's future.
Ukraine has successfully defended Kiev, and Russia has refocused its offensive on the country's east, but American officials warn of the potential for a prolonged conflict.
The new legislation will provide $20 billion in military assistance, ensuring a steady stream of advanced weapons that have been used to blunt Russia's advances.
There's also $8 billion in general economic support, $5 billion to address global food shortages that could result from the collapse of Ukrainian agriculture and more than $1 billion to help refugees.
Biden signed the measure under unusual circumstances. Because he's in the middle of a trip to Asia, a US official brought a copy of the bill on a commercial flight to Seoul for the president to sign, according to a White House official.
The logistics reflect a sense of urgency around continuing US support for Ukraine, but also the overlapping international challenges facing Biden.
Even as he tries to reorient American foreign policy to confront China, he's continuing to direct resources to the largest conflict in Europe since World War II.
Biden also signed an unrelated measure, one intended to increase access to baby formula at a time when supplies remain scarce in the United States. The legislation will allow government benefits from the Special Supplemental Nutrition Program for Women, Infants, and Children — better known as WIC — to be used to buy more types of infant formula.