Complex predicates, characterized by having two or more heads, are problematic for models of language that assume a neat division of labor between syntax and lexicon (Alsina et al. 1997). On the one hand, such predicates usually have many of the properties of a typical lexical unit, for example in exhibiting a unified argument structure. On the other hand, syntactically the constituents of complex predicates function separately. Various theoretical frameworks have been applied in an effort to understand the workings of such constructions. This paper examines argument structure in three construction types in Kalam, a language spoken around the junction of the Bismarck and Schrader Ranges in the southwest corner of Madang Province, Papua New Guinea. 1 Kalam belongs to the Trans New Guinea (TNG) family, which with upwards of 400 members is by far the largest of the many ‘Papuan’(non-Austronesian) families of Melanesia. Except for a branch in the Timor area, the Trans New Guinea family is confined to New Guinea and a few offshore islands.