Objective: Quetiapine is a recently introduced atypical antipsychotic. Although adverse effects are mainly mild, more serious infrequent adverse effects including leucopenia are mentioned. Method: We describe three case-reports concerning haematological adverse effects of quetiapine. Results: Quetiapine was associated with leucopenia in two patients and clinically apparent agranulocytosis in one patient. Conclusion: Although a definite association has not been proven, clinicians should be aware of the possibility of agranulocytosis while using quetiapine. Further post-marketing surveys are required.