To retrospectively assess the changes in total cholesterol levels after a hospital admission for an acute coronary event, 287 patients were identified who had one isolated event: 130 patients with acute myocardial infarction, 122 patients after coronary artery bypass graft surgery, 35 patients after percutaneous transluminal coronary angioplasty. To be included, patients had to have a total cholesterol measurement within the 3 months prior to hospitalization and periodically after the acute coronary event. Total cholesterol measurements were recorded during four time periods: 0-3 months before hospital admission (baseline); and 0-3, 3-6, and 6-9 months after the hospitalization. Mean total cholesterol value was used if a patient had multiple measurements during a time period. RESULTS There was no significant difference in the baseline total cholesterol levels among the three groups (acute myocardial infarction, coronary artery bypass graft surgery and percutaneous transluminal coronary angioplasty). In all three groups, there was a decrease in total cholesterol level after hospital admission compared to baseline (p < 0.0001). This decrease was significantly greater in coronary artery bypass graft surgery patients compared to the other two groups. Total cholesterol levels returned to baseline levels by 3 months after the hospitalization in all three groups. Total cholesterol decreased significantly from baseline in patients after an acute myocardial infarction; this decrease was significantly greater if they received thrombolytic therapy (p < 0.05). Total cholesterol returned to baseline 3 months after hospitalization in both groups. CONCLUSIONS During the 3 months following hospital admission for an acute coronary event, total cholesterol levels are not representative of the patient's baseline values. Management of hypercholesterolemia in this setting requires the use of baseline (preadmission) total cholesterol values.