Kukz is a previously undescribed southeastern Nilotic language of the Bari family. It is spoken in southern Sudan and northern Uganda. Kukz has a wide variety of verbal affixes. These affixes are involved in a number of vowel harmony and tone assignment patterns. In this grammar sketch, particular attention is paid to the qualitative morpheme, which functions quite differently in Kukz than in other Nilotic languages. In Kukz its distribution, both with respect to the verbs on which it can appear and the aspects in which it must appear, is related to a contrast between telicity and atelicity. If the performance of the verb has a potential end-point, and if the aspect is completive, then these conditions are marked by the presence of the qualitative morpheme. The syntax section focuses on problems in the distribution of the complementizers and in the use of two copula-like elements, one of which is clearly verbal and the other of which is a particle. The phonological section of this description is based on traditional elicitation from a consultant. The morphological and syntactic sections also draw heavily from texts of various types, ranging from traditional songs to electronic mail.