INTRODUCTION Second-hand smoke exposure has decreased in a number of countries due to widespread smoke-free legislation in public places, but exposure is still present in private settings like homes and cars. Our objective was to describe to what extent smokers implement smoking rules in these settings in six European Union (EU) Member States (MS). METHODS A cross-sectional survey was conducted with a nationally representative sample of adult smokers from Germany, Greece, Hungary, Poland, Romania and Spain (ITC six European countries survey, part of the EUREST-PLUS Project). We analysed data from 6011 smokers regarding smoking rules in their homes and in cars with children (no rules, partial ban, total ban). We described the prevalence of smoking rules by EU MS and several sociodemographic and smoking characteristics using prevalence ratios (PR) and 95% confidence intervals (CI) derived from Poisson regression models. RESULTS In homes, 26.5% had a total smoking ban (from 13.1% in Spain to 35.5% in Hungary), 44.7% had a partial ban (from 41.3% in Spain to 49.9% in Greece), and 28.8% had no-smoking rules (from 20.2% in Romania to 45.6% in Spain). Prevalence of no-smoking rules in cars with children was 16.2% (from 11.2% in Germany to 20.4% in Spain). The correlates of not restricting smoking in homes and cars included: low education (PR=1.51; 95%CI: 1.20-1.90 and PR=1.55; 95%CI: 1.09-2.20), smoking >30 cigarettes daily (PR=1.53; 95%CI: 1.10-2.14 and PR=2.66; 95%CI: 1.40-5.05) and no attempts to quit ever (PR=1.18; 95%CI: 1.06-1.31 and PR=1.28; 95%CI: 1.06-1.54). CONCLUSIONS Among smokers in six EU MS, no-smoking rules were more prevalent in homes than in cars with children. Whilst awareness about the health effects of exposure to tobacco smoke on children seemed to be high, more research is needed to better understand the factors that promote private smoke-free environments.