Signaling of relations is an open question in rhetorical structure theory. Discourse markers are the unmistakable signals of a relation. However, it may be argued that all relations – and not only those involving discourse markers – are signaled in some way. Based on this assumption, this article focuses on two causal relations, ‘Cause’ and ‘Result’, working on an RST double-annotated corpus in Spanish. The main objectives are to identify different signals of Cause and Result relations and to evaluate the (...) ambiguity resulting from those signals. Results demonstrate that a) almost all Cause and Result relations on the corpus are signaled; b) each signal obtains differentiated annotation agreements; and c) patterns of annotation disagreement are grounded in the nature of the signal and not in the relations’ semantic features. (shrink)