Background: Vaccinium arctostaphylos L. (Ericaceae family), locally named Qare - Qat is a shurb or woody bush which has been extensively used in Iranian folk medicine as antidiabetic and antihypertensitive agents for many years. Phenolics found in leaves and fruits of the plant are a specific group of secondary metabolites that plays an important role of antioxidant activity. Objective: Comparative study of phenolics, anthocyanins and flavonoids contents in V. arctostaphylos methanolic extracts and evaluation of antioxidant activities. Methods: Leaves and fruits of V. arctostaphylos have been collected from the high altitude areas of Ardabil (Hoor), Gilan (Masouleh and Asalem) and Mazandaran (Kelardasht) provinces in August 2007 and stored at -80°C until metabolites analysis. Then extraction was carried out with acidified methanol and the mixture was used for antioxidant activity and phenolics content assays by UV- Vis spectrophotometer. Results: The data indicated that fruits of Kelardasht genotype had the highest total phenolics content as gallic acid (42.73 ± 1.5 mg g-1 DW), anthocyanin content as cyaniding-3- glucoside (1.0± 0.07 mg g-1) and antioxidant activity (DPPH assay) of fruits of Kelardasht (IC50: 0.14 ± 0.07 mg ml-1) were highest in comparison to other genotypes. Leaves of Masouleh genotype had the highest flavonoid content as quercetin (2.9 ± 0.07 mg g-1 DW). Conclusion: It could be concluded that the leaves and fruits of V. arctostaphylos have high amount of phenolics and antioxidant activity. Therefore, this plant can be a potential source of antioxidant compounds for food and pharmaceutical industry.