SSPE is a chronic complication of measles with a delayed onset and nearly fatal outcome. This “slow virus infection” results from a persistent infection with an altered measles virus, that is harboured intracellularly in the CNS. Patients usually presents with cognitive decline and myoclonus but atypical presentations are also quite common. Our case is of a 9 year old male child , previously neurodevelopmentally normal, presented with 4 months history of frequent fall due to jerky movements of the left upper and lower limbs which progresses to involve left half of the body, reduced attention span, cognitive decline and loss of speech. During hospitalisation, despite treatment with antibiotics , steroids , and antiepileptics ,disease progressed with myoclonic jerks , altered sensorium and nally child became comatose. CSF study is normal but MRI and EEG shows abnormalities. Based on clinical features and history of exanthematous illness at 6 months of age, measles igG antibody titres in CSF were tested , which came to be highly elevated conrming SSPE.