A total of 399 consecutive episodes of bloodstream infections in adult patients with haematologic malignancies and solid tumours were evaluated prospectively over a 26-month period, with the aim of determining the clinical characteristics and the microbiological profile of the patients relative to neutrophil count. The overall 30-day mortality rate was 32% (35% in non-neutropenic patients vs. 26% in neutropenic patients, p=0.05). Main diagnoses were solid tumours (33%) and lymphoma (29%). Most of the episodes of bloodstream infection (58%) occurred in non-neutropenic patients. Acute leukaemia and bone marrow transplantation predominated in the neutropenic group. Non-neutropenic patients tended to be older and to have a higher frequency of solid tumours and advanced or uncontrolled diseases. Indwelling central venous catheters were present in 51% of the episodes, with a predominance of long-term catheters in neutropenic haematologic patients. Concomitant infections were observed more frequently in non-neutropenic patients. There were 1,040 noninfectious comorbid conditions, most of which were present in non-neutropenic patients. The causative pathogens were predominantly gram-negative bacilli (56%). Escherichia coli and Klebsiella pneumoniae were isolated more frequently from neutropenic patients, while Staphylococcus aureus and Acinetobacter spp. were more frequent in non-neutropenic patients. Seventy-four percent of the episodes of candidaemia occurred in patients with central venous catheters, with non-albicans strains predominating. The results of this study highlight the heterogeneity of cancer patients with bloodstream infections and the value of stratifying risk factors and aetiologic agents according to neutrophil count.