This study aimed to investigate the clinical and organizational impact of an active re-evaluation (on day 10) of patients on antibiotic treatment diagnosed with bloodstream infections (BSIs). A prospective, single center, pre-post quasi-experimental study was performed. Patients were enrolled at the time of microbial BSI confirmation. In the pre-intervention phase (August 2014–August 2015), clinical status and antibiotic regimen were re-evaluated at day 3. In the intervention phase (January 2016–January 2017), clinical status and antibiotic regimen were re-evaluated at day 3 and day 10. Primary outcomes were rate of optimal therapy, duration of antibiotic therapy, length of hospitalization, and 30-day mortality. A total of 632 patients were enrolled (pre-intervention period, n = 303; intervention period, n = 329). Average duration of therapy reduced from 18.1 days (standard deviation (SD), 11.4) in the pre-intervention period to 16.8 days (SD, 12.7) in the intervention period (p < 0.001). Similarly, average length of hospitalization decreased from 24.1 days (SD, 20.8) to 20.6 days (SD, 17.7) (p = 0.001). No inter-group difference was found for the rate of 30-day mortality. In patients with BSI, re-evaluation of clinical status and antibiotic regimen at day 3 and 10 after microbiological diagnosis was correlated with a reduction in the duration of antibiotic therapy and hospital stay. The intervention is simple and has a low impact on overall costs.