Working conditions of eldercare are often characterized by a high workload and different organizational approaches have been suggested to reduce the potentially negative health-related effects of such conditions. One of the suggested approaches involves reducing the exposure to such working conditions by reducing the number of working hours. However, the knowledge of the concurrent health-related effects of working fewer hours remains limited. This longitudinal study set out to examine the health-related effects of an intervention involving daily working hours being reduced from >= 7 to 6 h. Data came from an organizational intervention that included 68 women employed in the municipal eldercare. All employees retained full-time salaries and additional personnel were employed by the organization in order to provide full services throughout the intervention period. A broad range of biomarkers and self-ratings in questionnaires were obtained before the intervention, 6 months after the change, and 12 months after the initial change. Measurements among referents (n = 19), matched with respect to type of work, were performed at corresponding time points. Results from repeated measures ANOVAs showed significant interaction effects for diastolic blood pressure and HbA1c with these effects being primarily related to changes among referents. No other significant group differences were found. Time-related effects emerged in both groups but cannot be attributed to the intervention as such. To conclude, this study showed none of the hypothesized health promoting or other consistent effects of reduced working hours.