Factors affecting long-term absenteeism for non-accident-related sickness leave in a large, remotely located factory (Dead Sea Industry, Israel) were evaluated. About 10% (89 persons) of the workers were found to be on sick leave for more than 20 days/year. This group was designated as high absence workers (HAW). Most of the sickness absence were for repeated short-term leaves due to intercurrent diseases, rather than for continuous periods related to a major or single illness. Average cumulative duration of sick leave in this group was 54 days/year. The average number of spells was 11 per year (4.9 days/spell). There were significantly more HAW among skilled (relative risk, R.R. = 1.6) workers or shift workers (R.R. = 1.3), compared to white collar workers. There were significantly fewer HAW among workers 35-49 years of age (7.6%) than among younger (12.5%) or older workers (13.8%). Except for possible hearing loss in one worker, no occupationally related illness was identified. Sixty-six percent of the HAW took many sick leaves, over 20 days during the year following the study year, and 52% of this group took over 20 days in the preceding year (usually for minor diseases or complaints). This pattern of long-term sickness absence indicates that various socio-economic factors determine HAW to a greater extent than immediate occupational risks or health problems.