Many tropical ecosystems support exceptional levels of amphibian diversity, but in contrast to their temperate counterparts, many aspects of their biology are little studied and poorly understood. Demographic studies give valuable insights into the age structure and life histories of amphibian populations, thus they are of high importance in making accurate and precise conservation assessments in the light of current global amphibian declines. We analysed age structure and growth in a population of the viviparous caecilian Geotrypetes seraphini, a caecilian amphibian from Mount Cameroon, Central Africa, by using skeletochronology. We detected lines of arrested growth (LAG) in mid-body vertebrae and interpreted them as indicators of a seasonal growth pattern. We expect that LAG are materialized at a rate of one per year. In our sample male reach sexual maturity at an early age (age class 0+), whereas females mature later (age class 1+). Maximum longevity in our sample was estimated at 4+ years. Body size (total length) was significantly smaller in males than in females. Our study shows that skeletochronology is a highly suitable method to determine caecilian growth and age. Caecilian amphibians show a high diversity of reproductive modes including unusual brood care and parental investment strategies. In order to deepen our understanding of their ecology and evolution, many more demographic studies on other species and lineages are needed.