In patients with hematological malignancy (HM) developing acute respiratory failure (ARF) bronchoalveolar lavage (BAL) is considered as a major diagnostic tool. However, the benefit/risk ratio of this invasive procedure is probably lower in the subset of patients with acute myeloid leukemia (AML). The study was to analyze the yield of BAL performed in HM patients (n=175) with AML or lymphoid malignancies (LM) admitted in intensive care unit (ICU) for ARF and pulmonary infiltrates. BAL was performed in 121 patients (53/73 AML patients (73%) and 68/102 LM patients (67%)) without a definite diagnosis at admission or contraindication for fiberoptic bronchoscopy. Life-threatening complications were noticed in 12/121 patients (10%). The overall diagnostic yield of BAL was 47% (25/53) in AML patients and 50% (34/68) in LM patients. A microorganism was recovered from BAL in 23% (12/53) of AML patients and 41% (28/68) of LM patients (P<0.005). BAL results induced significant therapeutic changes in 17% (9/53) of AML patients vs 35% (24/68) of LM patients (P=0.039). This study underlines the rather low diagnostic yield of BAL for infectious diagnosis and the low rate of therapeutic changes induced by its results in AML patients with ARF admitted in ICU.