BACKGROUND: Metabolic syndrome is defined by insulin resistance and a clustering of other cardiovascular risk factors. Crocin is a carotenoid derived from the stigmas of the saffron flower and had previously been shown to affect lipid profile. However, the mechanism for this function is not well understood. The present trial aimed to investigate the possible effect of crocin on plasma levels of cholesteryl ester transfer protein and lipid profile in individuals with metabolic syndrome. METHODS: This was a randomized, double-blind, placebo-controlled, clinical trial consisting of an 8-week treatment with crocin, or placebo tablets between April and June 2014, in the Nutrition Clinic of Ghaem Teaching Hospital, Mashhad, Iran. Participants were randomly assigned to take a 30 mg/day crocin (n = 22) in the intervention group or placebo (n = 22) in the control group. Anthropometric, hematological and biochemical parameters were measured and recorded during pre and post-treatment periods. RESULTS: Whilst plasma cholesteryl ester transfer protein was increased in the group taking the crocin tablet by 27.81% during the trial period (P = 0.013), the difference between the crocin and placebo groups was not significant (P = 0.116). Moreover, the percent changes in cholesterol (P = 0.702), triglyceride (P = 0.080), low-density lipoprotein (LDL) (P = 0.986), high-density lipoprotein (HDL) (P = 0.687) and fasting blood glucose (P = 0.614) did not differ significantly between intervention and control groups. CONCLUSION: Although crocin supplements increased the serum cholesteryl ester transfer protein in patients with metabolic syndrome, this change was not significant between treatment and placebo groups.