In 1980 WHO defined disability as a functional limitation due to impairment, and handicap as the psychosocial disadvantage consequent to disability. This study was designed to investigate the advent of handicap in a group of adults physically disabled by poliomyelitis in childhood by comparing them to their age- and sex-matched siblings. An area survey was conducted in West Beirut and its Southern Suburb and 240 such disabled people and their siblings were identified and interviewed. Handicap was defined as disadvantage in six areas, namely, education, work, income, marital status, housing, and mental well-being. The differences between each disabled person and his/her sex-matched sibling were assessed. Significant differences were noted in employment (Odds ratio (OR) = 4.20, confidence interval (CI): 1.38-15.26), social class (OR = 2.67, CI: 1.11-6.79), income (OR = 2.88, CI: 5.57-113.3) and marital status for both the disabled people compared with their elder siblings (OR = 20.00, CI: 5.57-113.30) and for those disabled compared with their younger siblings (OR = 4.60, CI: 1.53-16.55). Multivariate analyses of the explanatory factors for each of these six areas of disadvantage among the disabled group showed that educational discrepancies cut across social class differences (OR = 1.90, CI: 1.00-3.61), income differences (OR = 1.44, CI: 0.97-2.14), and symptoms of depression (OR = 2.33, CI: 1.42-3.84). Marital-status disadvantage was related to lower income groups and disabled women (OR = 1.66, CI: 1.10-2.49; OR = 1.60, CI: 1.07-2.39).(ABSTRACT TRUNCATED AT 250 WORDS)