Organophosphorus (OP) compounds are used as pesticides are cause of accidental and suicidal poisoning, with high morbidity and mortality rates, especially in developing countries. Clinical manifestations include cholinergic syndromes, central nervous (CNS) system and cardiovascular disorders. Death is usually due to cardiovascular and respiratory failure. The aim of the present study was to predict requirement of ventilator support in OP poisoning patients. Prospective study of one hundred cases of OP poisoning admitted in the ICU, Mamata General Hospital, Khammam from January 2009- June 2010. Out of 100 patients 53 patients were selected for the study based on clinical history to predict requirement of ventilator support in OP poisoning. In the present study the majority of the patients in the study group were males but the percentages of the female patients ventilated were higher when compared with males. In the present study, the maximum patients were poisoned with Methyl parathion, followed by Quinalfos and with unknown compound. 28.3% patients showed mild GCS scoring and only one patient was ventilated, whereas patients with moderate score were maximum. The present study concludes that, the need for ventilatory support in organophosphorous poisoning was significantly more in patients who consumed Methyl parathion compound, presence of cardiovascular collapse, Glasgow coma scale score of <6.