Effect of shift work on worker's health, family and social life was investigated at a automobile manufacturing plant in Inchon. In total, 2488 shift workers and 599 non-shift workers completed self administered questionnaire in their sleep pattern, subjective gastrointestinal symptoms, prevalent chronic disease status, general well-being schedule, family and social life. More shift workers complained of sleep disturbance, poor sleep quality, tiredness at awakening, and sleepiness in work than non-shift workers. More shift workers also complained of gastrointestinal disturbance than non-shift workers. Worker's mental health was assessed by General Well-Being Schedule(GWB) questionnaire developed for the U.S. Health and Nutrition Examination Surveys(HANES I). The percentage of severely distressed shift workers was significantly higher than that of non-shift workers(p<0.01). Among subscores in General Well-Being Schedule, anxiety, depression, positive well-being, vitality, and general health subscale of shift workers were lower than those of non-shift workers (p<0.05). In terms of family and social life, there was no significant difference between two groups. Multiple logistic regression analysis was done for discrete variables which showed statistically significant difference between shift and non-shift group. The variables included in analysis were sleep disturbance symptoms, gastrointestinal complaints, and distress level calculated from GWB score. Age, tenure, smoking, alcohol drinking, and exercise were adjusted as confounding factors and odds ratios for above symptoms due to shift work were calculated. Odds ratios (ORs) for sleep disturbance symptoms ranged from 0.52 to 3.59. ORs for gastrointestinal complaints ranged from 1.19 to 1.34. OR for distress level was 1.31. We concluded that shift workers are suffered from physical and psychological ailments due to shift work and interventional methods for preventing worker's health from adverse effects of shift work are needed.