Introduction: the COVID-19 pandemic has left long-term sequelae, known as residual or prolonged COVID-19, which affect multiple organ systems and mental health. Nursing staff, being on the front line of containment, constitute a particularly vulnerable population. However, there are few studies that comprehensively address this problem in nursing professionals in Argentina.Objective: to analyze the health problems reported by registered nurses in the southern province of Santa Fe and their possible link to residual COVID-19.Method: a cross-sectional study with a mixed approach was conducted during the second half of 2025. A validated survey was administered to 358 nurses, assessing variables of mental and physical health, risk perception, and contextual characteristics. The analysis included descriptive statistics and a contextualized qualitative approach.Results: a high prevalence of mental health problems was identified: 48,3 % reported chronic fatigue, 34,6 % reported distressing memories, and 32,7 % reported excessive worries, with low treatment rates (≤9,2 %). In terms of physical health, difficulty concentrating (36,8 %), acid reflux (21,7 %), and high blood pressure (13,6 %) stood out. Paradoxically, 70,1 % did not express fear of reinfection. The study population was predominantly female (83,5 %) and had a high prevalence of multiple jobs (37,2 %).Conclusions: nurses have a significant burden of physical and mental morbidity consistent with residual COVID-19, exacerbated by critical healthcare neglect and precarious working conditions. These findings call for the urgent development of specific public policies for surveillance, comprehensive care, and occupational protection for this group.