Our objective was to assess the impact of selected geographic factors and patients' characteristics on thrombolysis rates in patients resident and hospitalised for acute myocardial infarction in three departments of the Rhĵne-Alpes Region (France). We used a two-level hierarchical model to estimate and explain geographic areas' specific effects. Old subjects and women were less frequently treated than young subjects and men. Severe, non-anterior and non-Q-wave myocardial infarctions were associated with lower thrombolysis rates. It was also lower in patients with a pulmonary chronic disease, a cancer, a peripheral arterial disease, a history of cerebrovascular accident or transient ischaemia attack, and in patients with a psychiatric disorder. After adjusting for patients' characteristics, significant variations in thrombolysis rates remained between geographic areas (up to 3.2 times). These variations seem to be partly explained by distance or isolation: a longer distance to the closest hospital or a high degree of isolation seem to lower the probability of thrombolytic therapy. Several other sources of treatment variation between the studied geographic areas remain unexplored. These factors, especially those that augment the delay to treatment, are to be identified in order to augment fibrinolysis usage and reduce inter-area heterogeneity.