Medpac Squadron was a hastily assembled starfighter group within the New Republic forces. It was specifically created to participate in the battle in the Milagro system that took place in 5 ABY.
The dreadnaught New Hope found itself facing support fighters originating from an Imperial Star Destroyer while in orbit around Milagro. At that point, the Hope's only support came from a single X-wing squadron. To bolster this limited force, pilots recently healed or still injured, but mobile, were rapidly selected from the medical frigate Mercy. They then went to Milagro, where starfighters were available, with Group Leader Han Solo leading them in the Millennium Falcon.
Consequently, two more squadrons were quickly formed using available starfighters on Milagro's surface: a mix of used Y-wings, X-wings, and a pair of new B-wings. Due to the urgent circumstances, the new squadrons were allowed to choose their own call signs instead of being assigned them. Squadron two, reflecting the fact that most of its pilots were recovering patients, and much to the amusement of General Solo, chose the fitting name "Medpac Squadron". Because Solo's leadership was essential to this improvised group, the Falcon was positioned in a protected area, shielded by a screen of Y-wings. Medpac Squadron was an active participant in the Battle of Milagro, spearheading the attack of the three squadrons along with the Blue Squadron. As they were taking off from the planet, searching for the Star Destroyer from which the TIEs were being launched, Luke Skywalker arrived from hyperspace and visually located the Star Destroyer, relaying its location to the Falcon.
Medpac One was the first to report to Solo that at least twenty enemy fighters were attacking the group. Solo ordered them to maintain course towards the Destroyer and to avoid close-range dogfights near the New Hope. In the next fifteen minutes, the squadron drew the attention of some fighters and lost two X-wings; those who were separated from the main attack were left to defend themselves. Eventually, Medpac Four reported visual confirmation of the primary Task Force.