en <strong>Aim</strong>: Considering the fundamental role of parents' function and family dynamics including the importance role of family communication pattern on preventing early-onset substance use in children, the present study aimed to determine the correlation between family communication pattern and mothers' preventive behavioral intention regarding preventing early-onset substance use in children. <strong>Methods</strong>: This cross-sectional study was carried out among 234 Iranian mothers in Tehran who were randomly selected to participate voluntarily in the study. The participants filled out a self-administered questionnaire including I- demographic information; II- family-based behavioral intention regarding preventing early- onset substance use in children; and III- family communication pattern. Data were analyzed by the SPSS software (ver. 21.0) using Pearson's correlations, independent t-test, and ANOVA at 95% significant level. <strong>Findings</strong>: The results reported a correlation between conversation (r=0.509**& P≥0.001), conformity orientation (r= -0.150*& P=0.022) and behavioral intention; as well as between conversation conformity orientation (r= -0.382*& P≥0.001), and conversation (r=0.218**& P=0.001), conformity orientation (r= -0.105& P=0.108) and age. <strong>Conclusion</strong>: The findings suggest that to develop a preventive program, it will be useful to increase family communication pattern, specially conversation orientation to prevent the onset of substance use in children. Family,Cognitive factors,Conformity orientation,Conversation orientation,Behavioral intention 33 43 http://hehp.modares.ac.ir/browse.php?a_code=A-5-14691-2&slc_lang=en&sid=4