Clozapine has recently been associated with venous thromboembolism. The aim of this study was to describe three elderly patients in whom olanzapine therapy was associated with venous thromboembolism. During a 4-month period at the same psychogeriatric clinic, three elderly patients (an 89-year-old male, a 78-year-old male and an 83-year-old female) developed deep venous thrombosis shortly after treatment with olanzapine was initiated. Two of the patients also had symptoms consistent with a diagnosis of pulmonary embolism. None had previously been diagnosed with venous thromboembolism. These cases indicate that venous thromboembolism might be associated with the use of olanzapine, at least in geriatric patients. Subjects treated with olanzapine should be monitored clinically for venous thromboembolism to ensure early detection and prompt intervention, and a possible discontinuation of treatment with olanzapine should be considered after a diagnosis of venous thromboembolism.