In hospitalized patients, the duration of antibiotic therapy for uncomplicated pneumonia is often longer than recommended in clinical guidelines. Consequences include increased risk of Clostridioides difficile infection and the emergence of antibiotic resistance. Reducing the duration of antibiotic therapy is an important goal of antibiotic stewardship (ABS) programs. To evaluate the impact of a computerized physician order entry (CPOE)-based ABS intervention on treatment duration in respiratory infections and on antibiotic use. A new type of prescription tool featuring a “soft stop order” was introduced into the CPOE system in the Respiratory Medicine department of a Thorax Center. The effect of this intervention was evaluated after 24 weeks using a retrospective before-and-after study design. A total of 210 patients were evaluated (preintervention group n = 109, postintervention group n = 101). Mean antibiotic treatment duration decreased from 9.59 days to 7.25 days (p < 0.001). It was reduced from 9.93 to 7.21 days (p < 0.001) in community-acquired pneumonia, 10.21 to 7.81 days (p = 0.05) in hospital-acquired pneumonia and 7.81 to 6.83 days (p = 0.14) in COPD exacerbations. The proportion of patients treated according to clinical guidelines increased from 35.8% to 69.3% (p < 0.001). The mean quarterly antibiotic use density was 41.2 RDD/100 PD (recommended daily doses per 100 patient days) before the intervention and decreased to 34.03 RDD/100 PD after the intervention (p = 0.037). Our study demonstrates the short-term effectiveness of a CPOE-based ABS intervention to reduce antibiotic treatment duration for uncomplicated pneumonia. This approach may be particularly suitable for hospitals with limited ABS resources. •Reducing antibiotic treatment duration for respiratory infections is an important target of antibiotic stewardship (ABS).•Electronic medical records and computerized physician order entry (CPOE) have the potential to support ABS programs.•This single-center study describes a CPOE-based ABS intervention featuring “soft stop order” and “clinical decision support”.•After its implementation, a significant decrease in treatment duration was observed in patients treated for pneumonia.•The results encourage further, multicenter investigation of the short- and long-term effects of this ABS approach.