This study investigates the function word deficits in aphasic patients and, in particular, agrammatic Broca's aphasics. Several explanations for the function word problem are addressed including a function word vocabulary deficit theory, a general syntactic deficit theory, and an abstract word deficit theory. Subjects with varying degrees of agrammatism were tested on a variety of production, comprehension, and reading, and syntactic tests which isolate semantic and syntactic aspects of both function and content words in order to better define the nature of the function word deficits in agrammatism.