Abstract: Pressure controlled-volume guaranteed mode combines the benefits of both pressure controlled ventilation and pressure controlled ventilation modes for the mechanically ventilated patients in ICUs Aim: is to assess weaning outcomes of the mechanically ventilated patient after using Pressure controlled ventilation-volume guaranteed and synchronized intermittent mandatory ventilation mode Design: A quasi-experimental research design. Setting: General intensive care unit at Assuit university hospital. Patients and methods: Purposive sample of 80 patients who were intubated for >24 hrs, divided into two groups equally, study group (PCV-VG group) and control group (SIMV-VC group). Pressure controlled ventilation-volume guaranteed mode was selected for study group and control group patients was mechanically ventilated on synchronized intermittent mandatory ventilation  mode Tool I : Patient assessment Tool II: Mechanical ventilator parameters assessment Tool III: Weaning outcomes assessment Results: Concerning weaning outcomes; 57% of SIMV-VC  group experienced weaning failure versus 35% in PCVG group, more than half of SIMV group re-intubated versus one third in PCVG group and less duration of mechanical ventilation for PCVG group versus SIMV group. Conclusion: Pressure controlled-volume guaranteed mode was more effective than synchronized intermittent mandatory ventilation mode in improving weaning outcomes Recommendations: Provide ICU nurses an educational program about Pressure controlled volume guaranteed and nursing care to improve waning outcomes.