The present article reviews the phenomenology of obsessive-compulsive checking, examining how action processing can be differentially affected across distinct checking subtypes. Checking is a normal phenomenon which ensures that an intended goal has been actually completed. Checking symptoms have consistently been connected to impairments in processing information related to self-performances. Theoretical and empirical work has explained compulsive checking as a result of various cognitive deficits related to action processing (e.g., low confidence in cognitive abilities, impaired memory for actions, abnormal reality monitoring, overactive action monitoring, defective goal processing). Such apparent inconsistencies are, however, in agreement with clinical and empirical observations highlighting substantial variability in the subjective experience preceding/accompanying checking. Many factors can in fact prevent the cognitive system from determining whether or not an intended goal has actually been achieved. We argue that several action processing mechanisms are likely affected in checking; the related subjective experience may vary accordingly.