Hypoglycemia has been reported to occur frequently among individuals with health-related occupations, especially hospital nurses. In this study, we investigated the risk factors of hypoglycemia. Both female hospital nurses and other female workers participated in this study, which included questionnaires, and daily blood glucose monitoring. Responses from 3, 415 workers were included for analysis. 2, 489 workers reported that they had never had hypoglycemic episodes (symptom-free group), while 926 workers reported that they had experienced hypoglycemic symptoms more than once. Of these workers, 207 had had episodes within one year of the study and had experienced them more than once a month (symptomatic group). Thirty-one volunteers were recruited from the above two groups-21 from the latter group and 10 from the former group- and daily blood glucose levels were determined: 6 days for nurses to cover three shifts (dayshift, nightshift and midnightshift) and 2 days for other workers. Nine of 21 volunteers from the symptomatic group had biochemical hypoglycemic reading(s) (<60 mg/dl) during the monitoring; however, none of 10 volunteers from the symptom-free group had such readings. These nine volunteers were found to have lower mean blood glucose levels (p<0.05) and lower minimum blood glucose levels (p<0.05) than other volunteers. Simple logistic analyses revealed multiple risk factors in the symptomatic group. By adjusting the confounding effects, these multiple risk factors were reduced into a small number of risk factors: occupation as a nurse, histories of hypotension and glucosuria, eating snacks, eating deserts, and insomnia. The present report clearly demonstrated that there are hypoglycemic-prone individuals among symptomatic female workers, who were shown to have multiple risk factors for hypoglycemic symptoms.