This paper describes the complex tense and aspect morphology in Nama, a previously undocumented Papuan language of southern New Guinea. Tense/aspect suffixes followed by agent/actor referencing suffixes occur in combination with one of two sets of patient referencing prefixes. Most of the tense/aspect suffixes mark two possible tenses, and the choice of a prefix from a particular set determines the appropriate interpretation. The distinction between imperfective and perfective aspect is central to the Nama tense/aspect system, and the forms of the perfectivity markers depend on the number category of the grammatical arguments: dual versus non-dual, which encompasses both singular and plural (i.e. more than two). At the same time, the agent/actor suffixes and patient referencing prefixes generally index two different number categories: singular versus non-singular. Each of the two basic aspects has three different tenses, with some other aspectual distinctions occurring only with singular arguments. A combination of imperfective and perfective marking is also used.