The little known Tutupaca volcano, located at the southern end of the Peruvian arc, is a dacitic dome complex that experienced a large explosive eruption during historical times. This eruption was characterised by a large sector collapse and an associated pyroclastic eruption. The spatial and temporal relationship between the debris avalanche and the pyroclastic density current deposits, coupled with the petrological similarity between the juvenile fragments in the debris avalanche, the pyroclastic density current deposits and the pre-avalanche domes, indicates that juvenile magma was involved in the sector collapse, and thus that both units were emplaced synchronously. This eruption probably represents the youngest debris avalanche in the Andes and was accompanied by one of the larger explosive events to have occurred in Southern Peru during historical times.