Introduction: Organophosphorus poisoning (OPP) is one of the common medical emergencies among rural population in India due to suicide attempts. The purpose of this study was to investigate the relationship between the initial emergency laboratory parameters (electrolytes, liver function test, random blood glucose (RBS), renal function test, Hb, RBC and WBC) and severity of organophosphate poisoning based on Bardin's Classification and type of OP compound consumed in patients admitted to emergency department with OPP. Materials and Methods: A retrospective observational study was done in OPP patients admitted to emergency medicine department. Based on Bardin's classification all OPP cases were classified into 3 Grades of severity of poisoning. [1][2][3] Hematological and biochemical parameters were compared based on this severity of poisoning. Results: With random sampling of 45 patients, 19 male and 26 female patients aged between 25-35 years, admitted with OPP were included in the study. The severity of poisoning was worst in females. The pseudocholinesterase, potassium and creatinine levels were significantly low in patients of grade 3 than grade 1 and grade 2 (p <0.05, 0.05 and 0.02 respectively) poisoning. Liver enzymes (AST, ALT and ALP) were elevated in Grade 3 poisoning patients much higher than Grade 1 and Grade 2 (p value 0.004, 0.002 and 0.06 respectively). Hyperglycemia was significantly observed in Grade 3 poisoning patients at the time of admission. (p value 0.03). There was significant hypokalemia (0.02), low RBC counts (0.02) and pseudocholinesterase levels (p value 0.01) in patients who had consumed chlorpyriphos and phorate. Conclusion: Emergency laboratory parameters in acute oraganophosphorus poisoning reflect the need for basic diagnostic facility in rural area. Laboratory parameters can also serve as possible predictive markers for severe outcomes and prognosis in OP poisoning. The knowledge of type of OP compound consumed can predict the severity of OP intoxication and need for emergency intervention.