Antibiotic resistance is a public health problem worldwide, given the inappropriate and indiscriminate use that has been given to them, so it is necessary to know the behavior and resistance mechanisms to develop strategies for the purpose of counteracting the increase in antibiotic resistance. The objective of this project was to characterize the resistance profile of isolated Gram-negative bacilli in a private IPS in Valledupar during 2018. It was an observational, descriptive, retrospective cross-sectional study with a population of 565 isolation of Gramnegative bacilli, for Statistical analysis was used frequency graphs and Stata 15.0 software. Among the results it was found that 85.6% (800) of the isolates corresponded to the enterobacteria having Escherichia coli in the first place with 43.52% and 14.4% (135) were identified as non-fermenters, finding Pseudomonas aeruginosa with higher prevalence with 47.62%. According to the variable location of the service and type of sample it was found that in the non-ICU service the most prevalent microorganisms was Escherichia coli with 67.7% in urine samples and among the non-fermenting gram negative bacilli the most prevalent was Pseudomonas aeruginosa With 73.1% in blood samples, in terms of bacterial resistance, Escherichia coli showed resistance in 43.52% to Ampicillin Sulbactam and 82.1% to Aztreonam, Pseudomonas aeruginosa showed resistance to Aztreonam in 47.62% and Ampicillin Sulbactam in 20.93 %. Conclusion it was possible to characterize the resistance of the microorganisms isolated from the different samples in the institution under study, being able to appreciate that the enterobacteria specifically Escherichia coli continues to occupy the first place in the isolation of the entity.