Background: Although in the past decade the management of invasive fungal infections has improved, a number of controversies persist regarding empirical antifungal treatment in critically-ill hematology patients. Aims: To identify key clinical knowledge to elaborate a set of recommendations, with a high level of consensus, necessary for the approach to fungal infections in critically-ill hematology patients. Methods: A Spanish prospective questionnaire, which measures consensus through the Delphi technique, was anonymously answered and e-mailed by 30 multidisciplinary national experts, all specialists in fungal invasive infections from six scientific national societies; intensivists, anesthesiologists, microbiologists, pharmacologists and specialists in infectious diseases. They responded to 10 questions prepared by the coordination group after a thorough review of the literature published in the last few years. For a category to be selected, the level of agreement among the experts in each category must be equal to or greater than 70%. In a second round, 73 specialists attended a face-to-face meeting held after extracting the recommendations from the chosen topics, and validated the pre-selected recommendations and derived algorithm. Results: Assess administering antifungal treatment to patients with high/medium risk factors and fever for over 4 days after onset of antibiotic therapy, and in the event of negative galactomannan or if no detection analysis has been performed and no relevant findings in the sinus and chest computed tomography (CT) have been detected, (1) in the case the patient did not receive prophylaxis, or was administered fluconazole, caspofungin treatment is recommended; (2) in the event the patient received prophylaxis with an azole with activity against filamentous fungi, the administration of liposomal amphotericin B is recommended and caspofungin as second choice therapy; (3) in the event that the prophylaxis received was an echinocandin, liposomal amphotericin B therapy is recommended and voriconazole as second choice. Assess administering antifungal treatment in patients with high/medium risk factors and fever for more than 4 days after onset of antibiotic therapy, and in the event of a positive galactomannan and/or sinus and chest CT suggests fungal infection caused by filamentous fungi, (1) in the event the patient did not receive antifungal prophylaxis or was administered fluconazole, the recommended treatment of choice is voriconazole or liposomal amphotericin B; (2) if the patient received prophylaxis with an azole with activity against filamentous fungi, the administration of liposomal amphotericin B with caspofungin is recommended and monotherapy with liposomal amphotericin B or the combination of voriconazole and anidulafungin are recommended as second choice therapies; (3) in the event an echinocandin was administered as prophylaxis, liposomal amphotericin B or voriconazole are the recommended treatments of choice. Consider the administration of antifungal treatment in patients with high/medium risk factors and fever for more than 4 days after onset of antibiotic therapy, and in the event of a negative galactomannan and the sinus and chest CT suggests fungal infection caused by filamentous fungi, (1) if the patient did not receive prophylaxis or was administered fluconazole, the recommended treatment of choice is liposomal amphotericin B or voriconazole; (2) in the case the patient received prophylaxis with an azole with activity against filamentous fungi, the administration of liposomal amphotericin B is recommended as first choice therapy and liposomal amphotericin B combined with caspofungin as second choice; (3) in the event an echinocandin was administered as prophylaxis, liposomal amphotericin B or voriconazole are the recommended treatments of choice. Conclusions: The empirical antifungal approach in critically-ill hematology patients requires the application of the broad range of knowledge and skills described in our recommendations and algorithm. These recommendations, based on the DELPHI methodology, may help to identify potential patients, standardize their management and improve overall prognosis. (C) 2016 Asociacion Espafiola de Micologia. Published by Elsevier Espana, S.L.U. All rights reserved.