The first case of acute watery diarrhea disease due to Aliarcobacter butzleri (formerly Arcobacter butzleri) in Ecuador is reported. An infant presented with moderate protein-calorie malnutrition, dehydration and anemia. A curved Gram-negative organism was isolated from stools, having been preliminarily identified by phenotypic characteristics. Definitive identification was achieved by multiplex PCR. Aliarcobacter butzleri was the only pathogenic microorganism isolated. No other entero-pathogens, enterovirus or parasites were found. Our findings strongly suggest that in this specific case, A. butzleri was the etiological agent. Further investigations are needed to develop standardized diagnostic protocols and to establish the prevalence and significance of Aliarcobacter infections in humans.