Introduction: Intermediate Syndrome (IMS) is a delayed-onset neuromuscular complication that develops 24–96 hours after acute organophosphate (OP) poisoning. It is marked by proximal muscle weakness and respiratory distress, significantly increasing the risk of morbidity and mortality if not recognized early. Although supportive care is the cornerstone of management, the underutilization of reliable early biomarkers hampers timely diagnosis and intervention, leading to poorer clinical outcomes in affected patients. Aim and Objective: This study aims to evaluate the effectiveness of the serum glucose-to-potassium (GLU/K) ratio as a predictive biomarker for IMS in patients with OP poisoning, thereby facilitating earlier diagnosis and intervention. Materials & Methods: A 12-month prospective observational study was conducted at Shri B M Patil Medical College, Vijayapura, involving 228 patients over 18 years with confirmed organophosphate (OP) poisoning. Patients with age under 18, pregnancy, diabetes mellitus, renal disorders, or non-OP poisoning were excluded. Key biochemical parameters including serum glucose, potassium, and the glucose/potassium (GLU/K) ratio were measured, and patients were closely monitored for clinical progression to Intermediate Syndrome (IMS). Results: Of the 228 patients, 21 (9.2%) developed IMS. All IMS patients exhibited significant hypokalemia (mean K⁺ = 2.8 mmol/L) and hyperglycemia (mean glucose = 226.4 mg/dL). The GLU/K ratio was significantly elevated in IMS patients (mean = 82.5) compared to non-IMS (mean = 40.5) with a p-value < 0.0001. ROC analysis showed an AUC of 0.910, with 94.3% sensitivity and 93.1% specificity. Conclusion: The GLU/K ratio is a reliable, accessible predictor of IMS, enabling early identification of high-risk patients. Early recognition through this biomarker can guide timely supportive interventions, especially in resource-limited settings.