This research examined the association between occupational fatigue and work absenteeism in 110 female assistant nurses of a high-complexity hospital in Chile. A sociodemo-graphic questionnaire and the Checklist Individual Strength (CIS) scale were used. The results showed that the predominant absenteeism range was 11-29 days. The highest means of fatigue occurred in those with seniority above 2 years, with more than 10 patients in charge and an annual contract. No significant difference was observed between the fatigue means concerning absenteeism, but a significant association was observed between physical fatigue (p = 0.040, OR = 1.054) and service seniority (p = 0.001, OR = 1.084) with work absenteeism. Finally, we can conclude that physical fatigue and seniority in the clinical service are significant risk factors for the occurrence of absenteeism.