Methyl mercury, a toxic by-product of the industry including gold processing bioaccumulates in fish and shellfish that when ingested bio-concentrates in the body eventually causing appalling neurologic disorders. This study prompted by the consecutive deaths of two Surigaonon-Manobo siblings from conditions suggestive of neurologic pathology aimed to: (1) document existence of neurologic morbidities indicative of mercury toxicity with assessment of the observable symptoms at selected indigenous communities in Mindanao, Philippines where small-scale gold mining takes place and (2) measure mercury levels in the hair of living subjects and river sediments at the research locale. Following proper entry protocol and securing of informed consent, affected adults, responsible adults in case of children and relatives of those who died from similar conditions were interviewed, government records reviewed. Identified were 31 cases in 22 families, 71% males mostly 0-5 years old. Photo and video images of subjects who displayed the alarming symptoms were taken in situ. Symptoms develop at 6-9 months after birth suggesting mother-offspring transmission through the breast milk. Starting to appear around 1986, majority (54.8%) manifested the symptoms in 2000-2010; 48.4% died in 2005-2015. Sometimes affecting all siblings, in some families no children were left alive. Hair samples from three living subjects and sediments from nearby bodies of water tested positive for mercury. It is concluded that the likely cause of the dreadful morbidities and children’s deaths is mercury toxicity of anthropogenic origin. A more intensive investigation is recommended to identify the cause and bring to an end the children’s deaths and devastating neurologic abnormalities documented herein.Keywords - Environmental Toxicology, mercury toxicity, methyl mercury toxicity, neurologic morbidities, small-scale gold mining, indigenous community, Surigaonon-Manobo, Mindanao, Philippines