Background <p>Emergency medical service nurses worldwide face continuous high-stress situations caused by critical incidents that can overwhelm them emotionally and affect their daily functioning and sustainable employability. Repeated exposure to these incidents negatively impacts their mental health. The COVID-19 pandemic has further exacerbated these issues, with high prevalence rates of insomnia and fatigue among emergency medical service nurses serving as key predictors of mental health problems. Until now little is known about the mental consequences of the COVID-19 pandemic on EMS nurses. This study, the first of its kind in the Netherlands, aims to assess the prevalence of insomnia, fatigue, and symptoms of mental health problems and identify associated risk factors.</p> Methods <p>A national cross-sectional study was conducted in the Netherlands in spring 2022. Data were collected through an online survey among emergency medical service nurses covering personal characteristics as well as validated scales on insomnia, fatigue, anxiety, depression, and Post Traumatic Stress Disorder.</p> Results <p>Prevalence rates were 39.2% for insomnia, 32.5% for fatigue, 18.4% for anxiety, 16.2% for depression and 10% for Post Traumatic Stress Disorder. Not recovering from COVID-19 was linked to higher odds of fatigue, while living alone was associated with insomnia. Working as an emergency medical dispatcher and more work experience were linked to increased fatigue. Regional differences in emergency medical services organizations and full recovery of COVID-19 showed to result in lower odds of insomnia in ambulance professionals.</p> Conclusions <p>Insomnia and fatigue are prevalent among emergency medical service nurses. These conditions heighten the risk of severe mental health problems and potential sickness leave. Further research is needed to explore factors contributing to these issues and to develop targeted interventions supporting professionals sustainability.</p> Clinical trial number <p>Not applicable.</p>