AbstractWe examine factors that influence male mating success in the glass frog Centrolene savagei; in addition, we describe courtship behaviour, oviposition and early parental behaviour. Fieldwork was conducted in the Colombian Andes during the rainy season from April 2006 to January 2011. Larger males had more chances of mating than smaller males; neither the height of calling site nor number of nights calling influenced the male mating success. Apparently, females choose males on the basis of call frequency attributes. Ours is the first study in glass frogs to report mating success skewed toward larger males. Courtship behaviour includes acoustic signals and visual displays. Additionally, we recorded an unusual routine interruption of amplexus by the male, and a synchronized behaviour between the female and male that indicates the beginning of male parental behaviour.Keywords: amplexus interruptionCentrolenidaeColombiacourtship callfemale choicevisual display AcknowledgementsSpecial thanks to C. Jaramillo, V. Hidalgo, A. Velez, C. Cordoba and N. Valencia and her family, for friendship, logistical support and/or help in the study area Yotoco. We also thank to C.A. Chica, C. Solano, C.A. Duque and J. Velasco for help in field sampling. Discussions with S.M. Durán and E. Salazar improved former versions of this manuscript. Special thanks to K. Kaiser, J. Delia and D. Forester for assistance with English and discussion of our results. This research was conducted under the agreement 086–2005 between the Asociación de los ríos MediaCanoa y Yotoco (ASOYOTOCO) and the Corporación Autónoma Regional del Valle del Cauca (CVC), and the Project "Herramientas de manejo del paisaje en fragmentos de bosque seco tropical y en la cuenca media de los ríos Chamberí, Barbas y Nima" supported by Universidad del Valle – Instituto Alexander von Humboldt – Cuarto objetivo (CI: 7710). We gratefully acknowledge the Universidad Nacional de Colombia campus Palmira, Valle del Cauca, the CVC and the Comité Administrativo de la Reserva Forestal Natural Bosque de Yotoco (CYRNI) for allowing us to work in the Reserva Forestal Bosque de Yotoco, and to the owner of Finca Piedramesa for allowing us to work on his land. Fieldwork of D. Osorio and A. Quintero in Filandia was supported by a grant from the Instituto Alexander von Humboldt (Colombia). The Instituto Colombiano para el Desarrollo de la Ciencia y la Tecnología "Francisco José de Caldas" COLCIENCIAS provided economic support during the doctoral studies of FVS. Scholarship grant support of MRC is provided by the CNPq (proc. 476789/2009–5). PDAGC is in receipt of a PhD scholarship (process 5725/10-0) from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). Equipment donated for IdeaWild to FVS, AQA and DOD was used during fieldwork. JARM and SEL thank the communities of Alto Bonito and El Águila for allowing us access to their land to search for frogs. This study was partially funded by the Facultad de Ciencias, Universidad de los Andes (to FVS), and the Vicerrectoría de Investigaciones y Postgrados of the Universidad de Caldas, Colombia (grant VIP-0224208).