Invasive fungal infections (IFIs) in patients with haematological malignancies are difficult to diagnose and outcome is often fatal. Over the 7-month study period, 117 cases with haematological malignancies receiving systemic antifungal treatment were included. Data regarding antifungal agents, dosage and reason for administration were recorded. Fungal infections in study patients were classified as possible, probable or proven according to recent European Organization for Research and Treatment of Cancer criteria. During the study period, 690 cases with haematological malignancies were admitted. A total of 117 cases received systemic antifungal therapy. Twenty-four of 117 patients (21%) had possible, six (5.1%) had probable and four (3.4%) had proven IFI. Seven of 10 probable and proven infections were caused by Candida spp., 2 by Aspergillus spp. and 1 by a fungus belonging to Zygomycetes. Fifty-two of 117 patients (44%) received antifungal prophylaxis, 81 of 117 (69%) received empirical (31/117; 26%) or pre-emptive (50/117; 43%) antifungal therapy and four of 117 patients (3.4%) directed antifungal therapy. Mostly, systemic antifungal therapy was administered empirically or pre-emptively. Twenty-nine per cent of cases receiving systemic antifungal treatment met the international consensus criteria of mostly possible IFI, whereas 71% did not. Proven invasive fungal infections were rare.