Background: - Suxamethoneum is a depolarizing muscle relaxant first introduce into clinicalrnpractice in 1951, it remains the drug of choice in clinical situations in which rapid paralysis andrnair way control are priorities. The administrations of succinylcholine may produce post-operativernmyalgia. Post-operative myalgia is thought to be caused by motor units firing at physiologicalrnhigher rate following Suxamethoneum administration, leading to unsynchronized musclerncontractions causing shearing forces of skeletal muscle fibers. The postoperative myalgia isrngeneralized aches and pains that commonly occur 24 to 48 hours after SuxamethoneumrnObjectives: - To assess the magnitude and associated factors of Suxamethoneum induced post-rnoperative myalgia in adult elective surgical procedures that were under gone from January 1,rn2017 to March 1, 2017 in Zewuditu memorial hospital, Addis Ababa, Ethiopia.rnMethod:-On 283 eligible patients Hospital based cross sectional study was conducted fromrnJanuary 1, 2017 to March 1, 2017 G.C at Zewuditu Memorial Hospital, using structuredrnquestionnaires and checklists and data were collected from all elective surgical patients whornfulfill the inclusion criteria during study period and the magnitude of post-operative myalgia wasrncalculated (%), associated factors with myalgia was investigated. Multivariate logistic regressionrnanalysis was conducted to identify significant predictors based on p-value less than 0.05 withrn95% confidence level.rnResults:-Among 160 elective surgical patient the magnitude of Suxamethoneum induced postrnoperative myalgia in the first 24 to 48hours were in 92(57.5%) and in which at 24hour thernmagnitude were about 84(52.5%) where as at 48 hour 74(46.2). The independent predictors ofrnSuxamethoneum induced post operative myalgia in this study are being female, incidencernfasciculation during induction and analgesia preoperatively.rnConclusion and recommendation:-The magnitude of Suxamethoneum induced postrnoperative myalgia in the first 24-48hrs was higher. To minimize the magnitude ofrnSuxamethoneum induced post operative myalgia and post operative patient discomfort differentrnprevention techniques should be applied. If possible it better to avoid the use of Suxamethoneumrnregularly for elective surgical patients.rnIt is also recommended that premedication of patients with analgesic agent before inductionrnanesthesia and defaciculat with NDNMBA.