Despite the widespread assessment of physical fitness in occupational medicine and health services, only a few validity studies have been made of the fitness tests used in relation to job demands. The purpose of this study was to assess the physical fitness of female home care workers (n = 132) in relation to age and to evaluate whether the fitness tests used predict work ability over a 5-year period of follow-up. Muscle endurance declined by 18% to 37%, and isometric muscle strength by 10% to 18%, from the youngest (21 to 35 years) to the oldest (45 to 59 years) age group. The proportion of those subjects who could be classified below the average age-related fitness categories according to the maximal oxygen consumption was highest (50%) for the 21-to-35 age group. The logistic regression model showed that obesity (odds ratio [OR] = 7.51) and poor results on the sit-up (OR, 8.9), balance (OR, 6.5), and weight-lifting (OR, 4.6) tests predicted the highest risk for reduced work ability, according to the work ability index used in the 5-year follow-up. Moreover, average results for the trunk side-bending test (OR, 4.6), poor results for the squatting test (OR, 3.8), poor knee extension strength (OR, 4.2), and the average maximal oxygen consumption (l.min-1) (OR, 3.1) indicated a high risk for reduction in work ability. The physical fitness tests were strongly associated with the physical demands of home care work and were relevant for the evaluation of work-related fitness among home care workers.