Introduction & Background: Breast cancer is known as one of the major causes of mortality among women. Early detection has been shown as the most effective strategy to reduce breast cancer mortality. Digital mammography is a new technology that uses high resolution and contrast devices. The aim of this research is to apply Wavelet Transform (WT) to enhance image resolution for better lesion detection. Patients & Methods: Since digital mammography is not available from local clinics, we used mammon-grams from Mammography Image Analysis Society (MIAS) database in our research. At first, median filter was used several times to reduce noise in mammogram images. Then the mammogram histogram was equalized and WT was used to enhance the imp-ages. The enhancement technique used, was local and adaptive for each of the sub-band images created after applying the WT multiresolution analysis. Afterwards an adaptive threshold according to the highest gray level of the image was used to save them, so that no probable micro calcification in the images would be lost. As a result, the contrast of images and the differ-emcees between benign and malignant abnormalities are highlighted for better visualization. Results: This procedure was implemented on 85 imp-ages from MIAS. In 78% of cases, the processed images were better than before. Conclusion: By using digital image processing tech-inquest on digital mammography, it is possible to in-crease contrast, to zoom on desired regions, to measure lesions, and to enhance images for better inter-predations.