Artifacts on mammographic images detract from the overall quality of the images and often present clinical and technical troubleshooting difficulties for the interpreting radiologist, technologist, and medical physicist and for the equipment and processor service personnel. This presentation demonstrates several types of mammographic artifacts that may pose a clinical challenge. They are arranged in the following categories: (1) particularly dangerous artifacts, (2) masses, (3) calcifications, (4) density variations, and (5) miscellaneous artifacts. Examples of such findings as summation shadows, normal anatomic variations, and incorrect positioning are also demonstrated as artifacts in this guide, because they may affect image quality or patient radiation dose. Under the Mammography Quality Standards Act, the lead interpreting physician has the responsibility for ensuring that the facility meets quality assurance requirements and is required to follow up with the technologist on poor-quality images. It is vital to recognize and correct for artifacts, whether they simulate non-existent lesions or obscure real pathology, because misinterpretation can lead to undesirable consequences.