Organophosphorus compounds are widely used pesticides. They are associated with a significant risk of acute intoxication. Oxidative stress is a contributing factor of acute organophosphorus poisoning morbidity and mortality. L-carnitine was found to have free-radical scavenging and antioxidant properties. Therefore, we aimed to evaluate the efficacy and safety of L-carnitine as an adjuvant in treatment of patients with acute organophosphorus poisoning. A randomized clinical trial was conducted on 30 patients suffering from acute organophosphorus poisoning admitted to Poison Control Center, Tanta University Emergency Hospital, Egypt, from April 2017 till January 2018. Patients were randomly divided into two equal groups. Group I received the standard treatment only and group II received the standard treatment plus L-carnitine in a dose of 1gm/8 hours IV.At time of admission, malondialdehyde, reduced glutathione, serum total antioxidant capacity and psudocholinesterase enzyme activity registered no significant difference between the two studied groups. After treatment, malondialdehyde, reduced glutathione and serum total antioxidant capacity showed significant improvement in group II. The mean value of atropine dose in group II (5.6mg) was significantly lower than group I(10.9mg). We concluded that the use of L-carnitine improved the antioxidant status and reduced total atropine dose required for treatment of patients with acute organophosphorus poisoning.