Cold plasma treatment of wounds is gaining much interest, because it will offer a noncontact, painless, and harmless therapy to manage large-area lesions (burn wounds and chronic ulcerations). One of the important issues in plasma wound healing is the safety of the method. In this paper, we study in vitro the effects of plasma treatment on cell death, proliferation, and wound healing. We performed a parametric study of plasma-treated 3T3 fibroblast cells. For the treatment, a cold atmospheric plasma needle (13.56-MHz microjet in helium) was used. Cells were cultured in six well plates and subsequently deposited on the bottom of the well. As a wound model, a scratch was made in the cell culture. Then, the proliferation of the cells from the sidewalls into the scratch was observed by microscopy. It appeared that plasma treatment stimulates the proliferation of cells into the scratch. This suggests that plasma treatment could result in accelerated wound healing.