Background: Due to the higher susceptibility of metabolic syndrome (MS)-afflicted patients to different metabolic abnormalities, treatment programs are vital parts of MS management. One of the possible adjunctive therapies is taking cranberry supplements as important sources of polyphenols that bear antioxidative and health-promoting properties.Objectives: The aim of this study was to evaluate the effect of cranberry extract on some components of metabolic syndrome.Patients and Methods: In a randomized, double-blind placebo-controlled clinical trial, 48 obese and overweight females diagnosed with MS were assigned into two groups to receive cranberry supplement or placebo for an eight-week period. Serum glucose, lipoproteins, inflammatory markers and blood pressure were evaluated at the baseline and at the end of the treatment phase.Results: Cranberry supplements had no effect on any of the variables including glucose, insulin, malondialdehyde (MDA), high-sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6), and blood pressure, except for high-density lipoprotein cholesterol (HDL-c), which significantly increased (P < 0.05) at the eighth-week period compared with the placebo samples.Conclusions: The results of the present study revealed that cranberry supplement might only ameliorate low HDL-c as a component of metabolic syndrome, and not the other risk factors of MS.