Background: Tobacco smoke exposure (TSE) harms children, who are often "captive smokers" in their own homes. Project Zero Exposure is a parent-oriented, theory-based intervention designed to reduce child TSE. This paper reports on findings from the pilot study, which was conducted in Israel from 2013 to 2014. Methods: The intervention consisted of motivational interviews, child biomarker and home air quality feedback, a Web site, a video, and self-help materials. The primary outcome was child TSE as measured by hair nicotine. Secondary outcome measures were air nicotine and particulate matter, parental reports of TSE, parental smoking behavior, and TSE child protection. A single-group pre- and posttest design was used. Results: Twenty-six of the 29 recruited families completed the study. The intervention was feasible to implement and acceptable to participants. Among the 17 children with reliable hair samples at baseline and follow-up, log hair nicotine dropped significantly after the intervention (P = .04), hair nicotine levels decreased in 64.7% of children, and reductions to levels of nonexposed children were observed in 35.3% of children. The number of cigarettes smoked by parents (P = .001) and parent-reported child TSE declined (P = .01). Logistical issues arose with measurement of all objective measures, including air nicotine, which did not decline; home air particulate matter; and hair nicotine. Conclusions: A program based on motivational interviewing and demonstrating TSE and contamination to parents in a concrete and easily understandable way is a promising approach to protect children from TSE. Further research is needed to enhance current methods of measurement and assess promising interventions.