Background: Metabolic syndrome is a global public health problem affecting both developing and developed countries with major consequences on human health, social and economic development. In Ethiopia although there is an increase in the prevalence of metabolic Syndrome due to epidemiologic transition, there is no study that evaluated the effect of interventions. This study aimed to assess the effect of nutrition behaviour change communication on metabolic syndrome and its markers. Method: A individually randomized controlled trial was conducted among Ethiopian adults working in Jimma University from mid of September 2015 to December 30, 2015. A total of 224 participants were randomly allocated into intervention (n=112) and controls (n=112) groups. The list of administrative and academic staff involved in the baseline survey was used as a sampling frame. Data on socio-demographic, anthropometric, biochemical and clinical parameters were collected using trained data collectors. Difference in the differences in metabolic syndrome and its components between baseline and end line were compared by the intervention status. Multivariable logistic and linear regression models were used to isolate independent predictors of metabolic syndrome and its components, respectively. Results: Overall, there was significant difference (P<0.001) in the prevalence of metabolic syndrome between intervention (11.6%) and control groups (37.5%) on the end line survey. On multivariable logistic regression analyses, control groups were 8.5 times more likely to have metabolic syndrome compared to intervention groups (AOR=8.53, 95%CI: 3.60, 20.21, P <0.001). There was a significant mean difference in differences in most components of metabolic syndrome and other lipid profiles except HDL (P=0.717) in the intervention group. The mean difference in differences in waist circumference was 6.3 cm (P<0.001), while that of systolic blood pressure (BP) and diastolic BP were 6.1 mmHg (P< 0.001) and 3.6 mmHg (P=0.001), respectively. Likewise the difference of differences between intervention and control groups was 30.7 mg/dl (P<0.001) for T.Cholesterol, 55.5 mg/dl (P<0.001) for triglycerides, 21.9 mg/dl (P=0.015) for LDL and 22.2 mg/dl (P<0.001) for fasting blood sugar. Further multivariable linear regression analyses showed that after adjusting for many variables, there was a significant difference in difference between intervention groups in components of metabolic syndrome. For the intervention group the mean difference in differences was 6.1cm (β=6.1, P<0.001) for waist circumference and 4.2 mm Hg (β=4.2, P<0.05) for diastolic blood pressure and 6.5 mmHg (β=6.5, P<0.001) for systolic blood pressure compared with controls. Similarly, the mean difference in differences was higher in the intervention group by 19.9 mg/dl (β=19.9, P<0.05) for FBS, 57.5 mg/dl for TG (β=57.5, P<0.05), 24.40 mg/dl for LDL (β=24.4, P<0.05) and 30.9mg/dl for T.Cholestrol (β=30.9, P<0.001). This trial is retrospectively registered on Pan African Clinical Trial Registration with unique identification number of PACTR202003465339638. Conclusion: There was strong positive effect of behaviour change communication on metabolic syndrome and its components. The results imply the need for enhancing behaviour change interventions using various strategies at the community and health facility levels to curb the emerging burden of chronic non-communicable diseases in Ethiopia. Future research should examine the sustainability of such behaviour changes using a community based study.