Background: High salt intake is one of the most important causes of some serious health problems. This study aims to evaluate the effects of a salt intake reduction intervention based on social marketing model in Ahwaz city, Iran.Methods: In this field trial experimental study, two similar residential complexes were selected using purposive sampling technique, and randomly assigned into intervention or control groups. In each residential complex, 130 women were selected using systematic random sampling. SMART model was applied as the social marketing planning tool. A formative research including audience, market, and channel analysis were conducted through two focus group discussions, a survey to identify cognitive and behavioral determinants of salt intake, and a salt intake assessment using 24-hour urine test for both groups. Based on the results of the formative research phase, an intervention plan was developed and implemented for 1 month in the intervention group. Post intervention assessment was conducted 1 month after the intervention by repeating the survey and the urine test. Statistical tests including independent T-Test and paired T-Test were used to compare the experimental and control groups. Results: Mean salt intake level before the intervention was 8574.41 mg/d in the intervention group and 8282.23 mg/d in the control group. Mean total scores of cognitive and behavioral factors was 25.32 and 26.41 out of 59 for the intervention and the control group respectively. After the intervention, daily salt intake decreased significantly by 1558.83 mg/d (16%) (P<0.001) and mean total scores of cognitive and behavioral factors increased significantly by 10.73 (p<0.001) in the intervention group.Conclusions: Despite the lack of public policies to decrease population salt intake, interventions based on social marketing can significantly reduce salt intake. However, long-term effect of such interventions will require further investigation.