Coronary artery calcium (CAC) deposits are an indicator of coronary atherosclerosis. Electron beam tomography (EBT) is currently the gold standard for CAC detection. There are no reports about the relation of physical activity (PA) to CAC, and there are only a few cross-sectional studies about the association CAC and other CHD risk factors. Purpose: To examine the relation of PA and other CHD risk factors as predictors of CAC. Methods: During 1987–2000, 41,044 individuals were examined at the Cooper Clinic. Of the participants free of cardiovascular disease, 4,607 participants (3,607 men and 1,000 women), age 47.7 ± 9.2 years with a range of 20 to 80 years, had an EBT scan at least one year after their baseline examination. We calculated CAC scores following a modified Agatston protocol; and classified individuals for the presence (2,558) or absence (2,049) of CAC. We used self-reports of walking, jogging, treadmill exercise, bicycling, stationary cycling, swimming laps, aerobic dance, and vigorous sports to calculate PA in metabolic equivalent hours per week; and assigned individuals to one of 5 groups (n): No activity (1,281) (reference group), Low 0.1–9.9 (938), Moderate-low 10–19.9 (1,056), Moderate-high 20–29.9 (617), and High ≥ 30 (715). We analyzed the data with an Ordianl Logistic Regression model with presence or absence of CAC as the dependent variable. We entered age and follow-up time as continuous variables; and gender, smoking history, high blood pressure (HBP), high total cholesterol (≥ 240 mg/dL or history of treatment), low HDL-C (< 35 mg/dL), diabetes, and obesity (BMI ≥ 30) as dichotomous variables. RESULTS: Odds Ratios and p values for the primary exposures were: Low PA (0.95, 0.57), Moderate-low PA (0.99, 0.99), Moderate-high PA (1.05, 0.60), High PA (1.16, 0.11), age (1.11, 0.0001), gender (5.66, 0.0001), smoking (1.27, 0.0001), HBP (1.37, 0.0001), diabetes (1.80, 0.0009), high cholesterol (1.55, 0.0001), low HDL-C (1.21, 0.0417), and obesity (1.08, 0.2515). CONCLUSION: Baseline PA was not related to CAC at follow-up, but that other CHD risk factors were associated with presence of CAC. Supported in part by NIH grants AG06945 and HL62508