Sudden infant death is a complex event characterized by biochemical features that are difficult to understand in general settings. Herein, we present a case report of a three-month-old infant who succumbed to sudden infant death syndrome (SIDS), focusing on the biochemical abnormalities identified through post-mortem analysis. The infant, previously healthy and meeting developmental milestones, was found lifeless in the crib during sleep. An autopsy revealed no anatomical abnormalities or signs of external trauma, consistent with SIDS diagnosis. Biochemical analysis of SIDS continued after post-mortem samples revealed dysregulation in neurotransmitter pathways, particularly serotonin, within the brain stem. These findings suggest a potential disruption in serotonin signaling, which may contribute to the vulnerability of infants to sudden death during sleep. Furthermore, metabolic profiling revealed deficiencies in enzymes involved in mitochondrial energy metabolism, particularly those related to fatty acid oxidation. These metabolic disturbances may compromise cellular function and contribute to the pathogenesis of SIDS. Environmental factors were also explored, with analysis revealing elevated levels of nicotine metabolites in post-mortem samples, suggesting maternal smoking exposure during pregnancy. Nicotine and its derivatives have known effects on neurotransmitter systems, potentially exacerbating underlying biochemical vulnerabilities in susceptible infants. This case report underscores the complex interplay of biochemical factors in the pathogenesis of SIDS and highlights the importance of multidisciplinary approaches in unraveling its mysteries. Further research is warranted to elucidate the precise mechanisms underlying these biochemical abnormalities and to develop targeted interventions aimed at reducing the incidence of SIDS and safeguarding infant health.