Classification, Clinical Features and Quality of Life in Late Poliomyelitis This study was designed to assess the clinical features and health-related quality of life in patients with late poliomyelitis. 28 patients with histories and examinations compatible with the diagnosis of poliomyelitis were included in the study. The limbs  were classified using five-level system (no polio, subclinical polio, stable polio, unstable polio, severe atrophy) based on the clinical history, physical examination and four extremity electrophysiologic study. Of the 112 limbs, 45 (40.2%) were unaffected by polio while 11 (9.8%) were severely atrophic. The needle recordings revealed polio sequele findings in 28 (33.8%) of the limbs not thought to have been affected by polio. The most common symptoms acknowledged were  muscle pain (80%), fatique (67.8%), joint pain (64%), increasing weakness (64.2%) and low-back pain (50%). 18 patients fullfilled the criteria of post-polio syndrome. All of them reported new increasing weakness. Of the 27 limbs experiencing new weakness, 12 (44.5%) were supposedly unaffected limbs. The Nottingham Health Profile questionnaire demonstrated least distress in the dimension of social isolation. Patients with post-polio syndrome has higher levels of distress in the dimensions of energy, physical mobility and pain than the patients without post-polio syndrome (p<0.05). In the dimensions of pain and physical mobility, items involving stairclimbing, walking  and standing were those contributed most to the level of distress. In conclusion, subclinical involvement should be considered while evaluating the patients with poliomyelitis. The impact of the post-polio symptoms is mainly on mobility-related activities and contributes negatively to quality of life.