Background and aims: Two inland dunes in the Netherlands receiving low (24) and high (41 kg N ha-1 yr-1) nitrogen (N) deposition were compared for N dynamics and microbial activity to investigate the potential effect of N on succession rate of the vegetation and loss of pioneer habitats. Methods: primary succession stages were sampled, including bare sand, and vegetation dominated by Polytrichum piliferum, Campylopus introflexus, lichens and grassess respectively, representing a series of vegetation types in undisturbed drift and sites with succession starting on bare sand containing virtually to organic matter. Microbial characteristics and potential N mineralization were analysed in a laboratory experiment. Results: Organic matter accumulated during succession, resulting in a lower pH and in higher microbial biomass (bacteria and fungi), respiration and net N mineralization. The increase in respiration and N mineralization was largely due to the development of an ectorganic layer in the middle stages of succession. The observed effects of N deposition were (1) decrease of microbial biomass, (2) higher net N mineralization per m2, (3) higher levels of free nitrogen in the soil, and (4) a higher microbial N:P ratio. Conclusions: Elevated N deposition leads to higher N availability which may cause accelerated succession.