Objective: This descriptive, cross sectional study was conducted to examine the effect of levels of self-efficacy on children's perceptions of pros and cons of smoking. Methodology: The sample was 233 fifth-grade students. Data were collected in September 2010 using the Socio-Demographic Data Collection Form, Self Efficacy Scale Child Form and Child Decision Balance Scale and analyzed via percentage calculations and t test with the SPSS 11.00 statistical package program. Results: Average age of the students participating in the research was 11.1±0.41, 49.8 % (n: 116) being female and 50.2 % (n:117) male. The difference between the score averages of the pros of smoking perceptions of children with a high self-efficacy level and of those with a low self efficacy level (t=2.117, p=.042) and the difference between the score averages of the cons of smoking perceptions of children with a high self-efficacy level and of those with a low self-efficacy level (t=2.206, p=.035) were found to be statistically significant. Conclusions: Children's positive perceptions of smoking were low and negative perceptions high when their self efficacy levels were high. Conversely, children's positive perceptions of smoking were high when their self efficacy levels were low.