Two trucks carrying medical supplies arrived in Mekele, the capital of Ethiopia's Tigray region on Tuesday, the International Committee of the Red Cross said.
The ICRC said this was its first aid delivery to the region since fighting resumed in August.
"ICRC's first medical supplies have just arrived in Mekele," the ICRC's spokesperson in Ethiopia, Jude Fuhnwi, told AFP.
"It is an enormous relief for us to deliver this cargo. The healthcare system in the region is under extreme pressure and these deliveries are a lifeline for people who need medical help," said Nicolas Von Arx, the head of ICRC's delegation in Ethiopia.
"This aid delivery is the first since the resumption of fighting last August and the signing of the Pretoria and Nairobi agreements," the ICRC added in a statement.
It was referring to the "Cessation of Hostilities" agreement signed by the Ethiopian government and the Tigray People's Liberation Front (TPLF) in South Africa on November 2 and a follow-up accord reached in the Kenyan capital on Saturday.
The warring sides had agreed in Nairobi to facilitate immediate humanitarian access to "all in need" in Tigray and neighboring regions with immediate effect.
Tigray, a region of six million people, has been suffering from a severe lack of food and medicine, as well as limited access to basic services including electricity, banking and communications, with the UN warning that many people were on the brink of starvation.
A humanitarian source told AFP late Monday that the UN's World Food Program (WFP) was preparing a convoy headed for the town of Shire, which has been under the control of federal forces and their allies since mid-October.
Earier Tuesday, Ethiopian Prime Minister Abiy Ahmed vowed to fulfil the commitments made in the peace deal and make "our promise a reality".
As well as the restoration of aid and a cessation of hostilities, the agreement calls for the disarming of TPLF fighters and the re-establishment of federal authority over Tigray.