Lumber spinal canal stenosis is an important cause of low back pain and it frequently presents with low backache with neurogenic claudication. Operative management of lumbar spinal canal stenosis by decompression surgery is an effective method. This prospective interventional (quasi experimental) study was performed in patient having history of characteristic clinical features like low backache with radicular pain, neurogenic claudication, signs of root compression, positive MRI findings attending in the department of Orthopaedic Surgery and Neurosurgery, Dhaka Medical College Hospital and NITOR. Dhaka, from July 2008 to June 2010. Thirty patients were evaluated among those 18(60%) were 50 years and above. Male to female ratio was roughly 9:1. About 87% of the patients had sensory deficit and 50% had neurogenic claudication. Majority (83.3%) of the patients at presentation had a suffering of 12 or >12 months. Diagnosis shows that 3.5% of patients had L4 lesion, 60% L5, 6.5% patients had L4 & L5 and 30% S1. Laminectomy was done in 43.3% of patients, laminectomy and disectomy in 30% and laminectomy, discectomy & foraminal decompression in 26.7% of patients. Relief of symptoms occurred in 25(83.5%) of patients. Over three-quarter (76.7%) of patients exhibited minimal disability and 23.3% moderate disability based on Oswestry Disability Index, while by MacNab criteria, most (80%) of patients was excellent, 10% good and another 10% fair. Repeated measure ANOVA statistics showed that mean Oswestry score decreased significantly from 54.5% at baseline to 22% at the end of 1 year (p<0.001).