Inclusion Criteria:

1. Women aged 18 -72 years at increased risk for breast cancer, defined by one of the following: 5 year projected Gail risk of greater than 1.67%, previous diagnosis of atypical hyperplasia (AH) or lobular carcinoma in situ (LCIS) ( per participating institution's pathology review), or ductal carcinoma in situ (participants could have received any type of surgery and radiation as long as they have an intact opposite breast.
2. The participant must have been properly informed of the study and must sign an informed consent to be able to be enrolled in the study. The informed consent document must be signed, witnessed, and dated prior to start of the study.
3. Normal physical exam and bilateral mammogram that shows no evidence of suspicious, malignant disease, or uncharacterized lesions within last 12 months and no evidence of any active other cancer.
4. ECOG performance status less than or = 1 (Karnofsky greater than or equal to 70%).
5. Participants must have normal organ and marrow function as defined below (up to 6 months prior to randomization): Leukocytes greater than 3,000/µL; Platelets greater than 100,000/µL; Total bilirubin within normal institutional limits; AST (SGOT) or/ALT (SGPT) </=1.5, institutional ULN; Creatinine within normal institutional limits; CPK, PTT, PT within normal institutional limits (up to 1 month prior to randomization).
6. The effects of atorvastatin on the developing human fetus at the recommended therapeutic dose are unknown. For this reason, women of child-bearing potential must agree to use adequate contraception (barrier method of birth control (IUD); abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her study physician immediately.

Exclusion Criteria:

1. Any type of active invasive cancer.
2. Bilateral mastectomy
3. Use of oral contraceptives; androgens; luteinizing-hormone-releasing-hormone (LHRH) analogs, prolactin inhibitors, antiandrogens, tamoxifen, raloxifene, or aromatase inhibitors. Women who discontinue these drugs at least 3 months prior to study enrollment will be eligible.
4. Chronic medical condition that requires regular use of statins or steroids (unless participants have discontinued these drugs 1 month prior to enrollment).
5. Participants may not be receiving any other investigational agents.
6. History of allergic reactions attributed to compounds of similar chemical or biologic composition to atorvastatin.
7. Psychiatric condition, including history of clinical depression, or addictive disorder that would preclude obtaining informed consent or would interfere with compliance. Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.
8. Pregnant women are excluded from this study because atorvastatin is a Class X agent with the potential for teratogenic or abortifacient effects. Because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with atorvastatin breast feeding should be discontinued if the mother is treated with atorvastatin.