This paper describes on-going work on extending the annotation of the Swedish Sign Language Corpus (SSLC) with a level of syntactic structure. The basic annotation of SSLC in ELAN consists of six tiers: four for sign glosses (two tiers for each signer; one for each of a signer’s hands), and two for written Swedish translations (one for each signer). In an additional step by Östling et al. (2015), all ¨ glosses of the corpus have been further annotated for parts of speech. Building on the previous steps, we are now developing annotation of clause structure for the corpus, based on meaning and form. We define a clause as a unit in which a predicate asserts something about one or more elements (the arguments). The predicate can be a (possibly serial) verbal or nominal. In addition to predicates and their arguments, criteria for delineating clauses include non-manual features such as body posture, head movement and eye gaze. The goal of this work is to arrive at two additional annotation tier types in the SSLC: one in which the sign language texts are segmented into clauses, and the other in which the individual signs are annotated for their argument types.