Recent studies in patients with obsessive-compulsive disorder (OCD) have shown that many compulsions are associated with urges rather than obsessions. Premonitory urges are uncomfortable sensory feelings or a rising inner tension, often likened to the urge to scratch, yawn or blink. We studied premonitory urges preceding mental compulsions in 19 patients with OCD and preceding eye blinks in 16 healthy controls. Urge intensity was assessed continuously over 20 min using a real-time urge intensity monitor; compulsions and blinks were measured as discrete events in a free compulsion/blinking and a compulsion/blink suppression condition. Urge intensity showed an inverted U-shaped relationship (increase then decrease) around compulsions within a time-window of approximately 60 s in patients with OCD and within 13 s around blinks in healthy controls. Urge intensity was higher during compulsion / blink suppression and varied more independently of compulsion execution in patients with OCD. There is a close temporal relationship between premonitory sensations and compulsion execution that changes when compulsions are suppressed, indicating that urge intensity might drive the execution of and is then alleviated by compulsions. Suppression weakens the association between urge intensity and compulsion execution.