The aim of this study was to describe the most frequently found bacterial microorganisms in bloodstream isolates taken from patients in intensive care units in Colombia and their resistance profiles. This was a multicentre descriptive observational study that was carried out between January 2001 and June 2008 with laboratory data from 33 participating hospitals in a surveillance network. The most frequently found microorganisms were coagulase-negative Staphylococci 39.6%, Staphylococcus aureus 12.3%, Klebsiella pneumoniae 8.2%, Escherichia coli 5.7%, Acinetobacter baumannii, 4.0% and Pseudomonas aeruginosa 3.8%. Coagulase-negative Staphylococci registered greater than 70% oxacillin resistance rate. S. aureus presented a change in its multiresistance profile during the years of follow-up. There was a trend towards a lower resistance rate among E. coli and K. pneumoniae isolates during the study period while A. baumannii carbapenem resistance rate exceeded 50%. There has been a change in the frequency of species being isolated with a higher frequency of enterobacteriaceae compared to Gram-positive microorganisms, in general with a high resistance rate.