BACKGROUND Organophosphorus (OP) compounds are insecticides which are widely used in agriculture. Acute organophosphorus poisoning is one of the important causes of morbidity and mortality in developing countries like India. Considering financial burden / availability of tests, we need cheap and easily measurable biomarkers for predicting prognosis / complications in a limited resource country, like India. We intend to correlate the levels of serum amylase in patients admitted with acute organophosphorus poisoning for predicting the severity of acute OP poisoning and also to correlate serum amylase association with respiratory failure. METHODS This was a prospective observational study. Total of 94 patients of OP poisoning admitted to KIMS Hospital, Hubballi between January 1st 2017 and December 31th 2017 were studied. Detailed history, clinical examination, and lab investigations like pseudocholinesterase, serum amylase and other relevant investigations were carried out. Peradeniya OP poisoning scale was applied to all the study subjects and the severity of OP poisoning was graded as mild, moderate, severe. Data obtained was analysed by different statistical methods. RESULTS OP poisoning was more common in adults of age group between 20 – 30 years, Incidence was more in male patients and mortality rate was 12.8 %. Mean values of serum amylase negatively correlate with pseudocholinesterase levels and it was statistically significant. Correlation between the severity of OP poisoning (based on Peradeniya score) and biochemical parameters like pseudocholinesterase, serum amylase was statistically significant. CONCLUSIONS The correlation between the severity of OP poisoning and biochemical parameter– serum amylase, was statistically significant and it was useful in predicting the development of respiratory failure. Pseudocholinesterase and serum amylase were also useful to predict the outcome of the patient. KEYWORDS Amylase, Organophosphorus Poisoning, Pseudocholinesterase, Peradeniya Score