Background: Neuromuscular blocking drugs (NMB) are very important adjuvant to general anaesthesia . Cisatracurium is a puried 1R cis-1'R cis isomer of atracurium introduced for clinical use in 1995 which is 3 to 5 times more potent and it provides faster onset, longer duration of action with good intubating conditions and is devoid of histamine release. The aim of the study was to compare the efcacy of Atracurium (0.5mg/kg) versus Cisatracurium (0.3mg/kg) as regard to onset of action, duration of action, intubating conditions, haemodynamic effects and signs of histamine release. Material and Methods: The study was designed as a prospective randomized single blinded study conducted in the Department of Anaesthesiology and Critical care, Silchar Medical College, Silchar, Assam after obtaining institutional ethical committee clearance. Only ASAI and II without any anticipated difcult airway (MPS-I) and who had given valid informed consent were included. 100 ASA I& II of age 18-60 years were divided into Group-A and Group-B of 50 in each group (n=50). Group-A received inj atracurium 0.5 mg/kg IV & group-B received inj cisatracurium 0.3 mg/ kg IV. Patients with cardiovascular or neuromuscular disease or on drugs known to interact with muscle relaxants, history of allergy to study drugs were excluded from the study. Results: Onset time, duration of action,intubating conditions, haemodynamic effects and signs of histamine release in both groups were recorded.In Group-A, mean onset time and duration of actions were 178.72±12.7 (sec) and 38.72±3.36(min), whereas in Group-B, it was 143.82±5.36(sec) and 56.78±1.93(min) respectively and statistically signicant (p<0.05). In Group-A, 70%(35) had excellent and 30%(15) good intubation grade whereas 92% (46) had excellent and 8% (4) good in Group-B with better haemodynaemic stability & no histamine release. Conclusion: In this study,we concluded that cistracurium 0.3mg/kg provided rapid onset, longer duration of action with excellent intubating conditions, better haemodynamic stability and was devoid of histamine release as compared to atracurium 0.5mg/kg .