Emotion recognition, an important aspect of social cognition, can be impaired already in early Alzheimer disease dementia and amnestic mild cognitive impairment (aMCI) and may underly social behavioral changes, which can increase caregiver burden. However, social behavior is difficult to assess in outpatient settings. We evaluated whether impaired emotion recognition is related to proxy-rated social behavioral problems and thus can serve as a marker of these changes. Emotion recognition was assessed with Ekman 60 Faces Test (EFT-total, 6 separate emotions) in patients (n = 31 AD; n = 37 aMCI) and healthy controls (n = 60 HCs). Social behavioral problems were rated by proxies with the neuropsychiatric inventory (agitation, apathy, irritability, disinhibition, and a sum score). It tested whether EFT scores differed between patients with and without behavioral problems. AD had worse EFT-total ( P <0.001), disgust ( P = 0.02), and fear ( P = 0.001) than HC, but not than aMCI, who did not differ from HC. AD displayed more disinhibition ( P < 0.05). EFT and neuropsychiatric inventory sum scores were not significantly correlated. Patients with apathy had lower EFT-total ( P = 0.02). Measuring emotion recognition adds value: it is impaired in early neurodegeneration and associated with apathy but not necessarily related to overall changes in social behavior in this population.