The U.S. Consumer Product Safety Commission reports about 60,000 emergency room visits for lawnmower injuries annually with 20% to children under 15 years. Employing a randomized pre-post control group design, the current study evaluated a 20-minute video intervention to increase parents' (n = 80) safety awareness and preventive actions. The setting was an outpatient clinic at a Children's Hospital. Differences favoring the intervention group were found for four of six behavior outcomes. For example, the proportion reporting never allowing children near operating mowers increased from half to two-thirds with no change among comparison group parents. In addition, significant increases in severity beliefs were found. The results provide formative support for the video intervention which possesses the key advantages of ease of use and constancy of message.