Background Patients with haematological malignancies are at high risk of invasive fungal infections. However, there is a lack of information about the utilisation of the recommended Australian antifungal prophylaxis guidelines in haematology outpatients. Objective To assess the impact of a weekly pharmacist review of high-risk adult haematology outpatients on the utilisation of appropriate antifungal prophylaxis. Setting Outpatient cancer centre, tertiary referral hospital in Sydney, Australia. Method A 3-month pre-and post-interventional study was conducted. A retrospective audit was conducted to obtain baseline utilisation of antifungal guidelines in adult haematology outpatients with acute myeloid leukemia, acute lymphoblastic leukemia and myelodysplastic syndrome receiving chemotherapy. This was followed by a weekly pharmacist review over a 3-month period of all eligible outpatients assessing the appropriateness of antifungal agent, dose, use of therapeutic drug monitoring and presence of drug-interactions/contraindications. Recommendations to physicians were conveyed weekly and outcomes recorded. Main outcome measure Appropriate utilisation of antifungal prophylaxis guidelines in outpatient haematology patients before and after implementation of a 3-month weekly pharmacist review service. Results Forty patients were included in the retrospective group, equating to 348 reviews, while 42 patients equating to 269 reviews were included in the prospective group. Appropriate utilisation of antifungal prophylaxis guidelines increased from 31 to 54% post implementation of a pharmacist review (Odds Ratio = 2.44, 95% Confidence Interval: 1.07-5.58, p = 0.0344). The most common reason for nonadherence to guidelines in both groups was lack of therapeutic drug monitoring and failure to prescribe antifungal prophylaxis where indicated. The percentage of appropriate use of antifungal prophylaxis in patients with acute myeloid leukemia increased from 13 to 46% (p value < 0.01) after pharmacist intervention. The pharmacist made 153 recommendations from 269 reviews, with a percentage uptake of 40%. Moderate to severe drug interactions were identified in 19 reviews from 10 patients. One major azole antifungal-chemotherapy interaction was avoided. Conclusions Appropriate utilisation of antifungal prophylaxis guidelines can be improved through a regular pharmacist review. Future studies should identify whether improving adherence to antifungal guidelines leads to improved patient outcomes.