Fluconazole is used for prophylaxis and treatment of invasive fungal infections (IFIs). The development of IFIs in patients being treated for haematological malignancies is associated with increased morbidity and mortality. As diagnosis of IFIs may be difficult, targeted prophylactic therapy is important in high-risk patients. Fluconazole has more predictable pharmacokinetics than other triazole antifungal drugs, but monitoring plasma concentration may be of use in assessing patient adherence to medication. A target range for plasma fluconazole during effective prophylactic therapy has not been established as yet. However, in patients prescribed fluconazole (200 mg/d) for prophylactic therapy the median (range) pre-dose plasma fluconazole concentration attained was 8.5 (1-20) mg/L.