OBJECTIVES: The aim of this study was to evaluate the difference in IgG glycan state between the patients with neurodegenerative diseases, the ones with neurological long COVID-19, and the control group. STUDY DESIGN: Cross-sectional study. PARTICIPANTS AND METHODS: The study involved 41 participants: 15 with neurological long COVID-19, 14 with neurodegenerative diseases, and 12 participants of control group. This study used the data collected through a questionnaire (age, sex, type of disease, duration of disease, symptoms of long COVID-19, COVID-19 vaccination and recovery from COVID19, comorbidities, therapy, body weight, height, smoking) and laboratory analysis of blood samples (G0, G2, S). RESULTS: The most common symptoms of long COVID-19 were cognitive impairment and chronic fatigue. There was no difference in age, sex distribution, BMI and smoking between participants, and metabolic diseases were more common in group with neurodegenerative diseases. Participants with metabolic diseases within the neurodegenerative diseases group had a higher middle rank of S glycans compared to the ones without metabolic diseases. Participants that did not have COVID-19 had higher G0 median, while participants that recovered from COVID-19 had higher G2 and S median. G0 median was higher in participants with neurodegeneration compared to control group. Glycan age median was higher in participants with neurodegeneration compared to the long COVID-19 group. Vaccination state did not affect any of glycans in any of the three examined groups. CONCLUSION: Compared to the participants with long COVID-19, participants with neurodegeneration have more pronounced proinflammatory glycan state than the control group. Participants with neurodegeneration also have higher glycan age than COVID-19 participants.