On June 30, 1997, at 2050 eastern daylight time, a Piper, PA-38-112, N2600N, struck a deer on the runway during takeoff, at the Johnston County Airport, Smithfield, North Carolina. The flight was conducted under the provisions of Title 14 CFR Part 91, with no flight plan filed. Visual meteorological conditions prevailed. The instructor and student pilot were not injured and the airplane sustained substantial damage. The flight originated at Raleigh-Durham International Airport (RDU), Raleigh-Durham, North Carolina at 2000. The instructor reported that he was giving instruction to a pre-solo student pilot at the Johnston County Airport, where they were conducting touch-and-go's. They were departing the airport to return to RDU, when they struck a deer. He stated that the student was at the controls at the time of the accident. The instructor stated that he did not see the deer, and "felt the impact, thinking they hit a pothole or a large rock." The student continued the rotation after impact, and then the instructor took the controls. He stated that he had to "lift the left wing and increase right rudder to maintain directional control." Once this was maintained, he stated that the airplane "lifted off and climbed out normally." The student then informed the instructor that they had struck a deer. The instructor looked at the wing and saw that it was dented. He stated that he "decided to land immediately to inspect the damage, but when they circled the field they could see the deer lying on the runway, about one third to one half of the way from the approach end of runway 03, and slightly left of the centerline." The instructor elected to return to RDU, where they had emergency personnel. He was uncertain of the condition of the gear. He informed Flight Service of the deer on the runway. They made an uneventful landing at RDU. The instructor reported that the left wing, forward of the landing gear, sheet metal, and, the left wing flap were dented, and that the main wing spar was bent.