Objective <p>Sarcopenia (loss of muscle strength/mass) reduces physical performance (walking, strength, mobility) and is common in Parkinson’s disease (PD), but data on newly diagnosed, untreated patients (“de novo”) are scarce. Fatigue is frequent in PD and linked to physical decline and malnutrition, key sarcopenia risk factors. We aimed to describe sarcopenia prevalence, malnutrition risk, and fatigue in de novo PD and explore differences based on fatigue presence.</p> Methods <p>Participants (<i>n</i> = 49) underwent physical tests [chair stand test (CST), hand grip strength, gait speed, Timed Up and Go test (TUG)] to assess sarcopenia. Malnutrition risk and fatigue were assessed using the Nutrition Form version 2 (MEONF-II) and the 16-item Parkinson’s Disease Fatigue Scale (PFS-16).</p> Results <p>Twenty (40.8%) showed probable sarcopenia. Eight (16%) had fatigue, and 8 (19%) were at risk of malnutrition. No significant differences in sarcopenia indicators were found between groups, but those with fatigue had lower physical performance (CST, <i>p</i> = 0.033; TUG, <i>p</i> = 0.011), slower gait speed (<i>p</i> = 0.050), and poorer appetite (<i>p</i> = 0.003).</p> Conclusion <p>A substantial proportion of de novo PD presented probable sarcopenia. Fatigue was associated with poorer physical performance and appetite but not sarcopenia. Whether fatigue increases risk of future malnutrition/sarcopenia is unclear due to cross-sectional study design. It should be further explored using a longitudinal study design.</p>