Abstract: An anti-microbial growth-inhibiting, skin-marking device for applying a marking agent to the skin of a patient who is to undergo a medical procedure such as radiation therapy. The skin-marking device has a flexible housing that contains a rupturable cartridge containing the marking agent and anti-bacterial, anti-fungal, and anti-viral solution. A flexible housing with a dry wick-type marking nib in one end which communicates with the interior of the housing and which is impregnated with a skin marking dye or ink. A cap for the marking device which is resistant to mocrobials, mold and mildew. The application end is used to tattoo, or paint or mark the skin of the patient, without penetrating the surface of the skin, applying the marking agent to mark treatment set-up points.