Bipolar disorder is a common psychiatric illness with a highly variable course and high rates of morbidity and mortality requiring lifelong treatment. It has an estimated prevalence of 1.6%–3.7%, and is an episodic illness interspersed with erratic cycles of mania and depression or mixed episodes. Valproate and quetiapine are commonly prescribed mood-stabilizing agents in psychiatry. These drugs are sometimes prescribed alone or in combination for treatment of mood disorders. Clozapine is one of the best known antipsychotic which has a risk of causing neutropenia, however the risk of neutropenia in newer atypical antipsychotics is less studied and relatively unknown. Quetiapine is an atypical antipsychotic that is widely used in the treatment of schizophrenia and mood disorders. We report a patient who had a diagnosis of bipolar disorder with neutropenia when receiving combined treatment with quetiapine and valproate. During treatment regular white blood cell count is necessary in these high-risk populations. Double –blind placebo controlled studies are needed on this issue.