ABSTRACT In Sweden, nature conservation management (NCM) is not applied to the extent needed to avoid negative impacts on biodiversity in voluntary set-asides and formal reserves. A limiting factor is the uncertainty of the costs for the operations caused by a lack of models for estimating costs and revenues in mechanized NCM. These may explain why some operations are highly profitable while others result in a net loss. Our aim was to compare harvester time consumption in NCM operations to final felling operations and estimate the added cost. Harvesting in 14 NCM stands and 399 final felling stands were studied using follow-up data. Harvesting intensity in NCM treatments varied generally between 25% and 50% of the standing volume. Time consumption in NCM operations was 1.1 to 1.4 times greater than in final felling, depending on management goal, machine size, and tree volume. Increased harvester time consumption is not the only factor influencing logging costs in an NCM operation. Compared to final felling, forwarder time consumption is expected to increase in the same way as in thinning operations. Field visits during spring 2022 allowed visual inspections of the stands after harvest and showed that NCM plans were generally followed with minor deviations.