<p>Knowledge of important demographic factors that influence the structure of animal populations is crucial for understanding species trends. Increased mortality during key life stages, such as hibernation, can have an impact on populations dynamics and yet, it is rarely estimated for most taxa. Using the hazel dormouse as a model species, an arboreal rodent that in Britain hibernates on the ground from late autumn to mid-spring, apparent survival estimates were modelled based on capture-mark-recapture methodology. Animals were marked with passive microchip transponders and future recaptures recorded in four populations in southwest England over periods between three and six years. In total, 465 hazel dormice were microchipped and 1054 encounter events were recorded. Apparent survival estimates were modelled according to age classes (juveniles and adults) and sex. Based on pooled data of the four populations sampled, apparent survival was estimated at 0.36 (0.29–0.44, 95% confidence interval). The results indicated variations in the survival estimates amongst the populations studied, and at two sites, age was detected as an important factor affecting survival performance of juveniles more than adults. The outcomes of this analysis showed similarities with other studies using different methodologies in Britain and continental Europe. The findings of this study indicate that apparent survival rates amongst hazel dormice are relatively low and that this can present challenges for species that depend heavily on yearly reproductive success to self-regulate and maintain viable populations.</p>