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Remote ischaemic preconditioning (RIPC) describes the phenomenon in which brief ischemia of one tissue or organ protects remote organs from a sustained episode of ischemia. Studies suggest that myocardial injury sustained during coronary artery bypass graft (CABG) surgery is associated with worse clinical outcomes. We conducted a single-blinded randomized controlled ‘proof-of-concept’ study to determine whether RIPC, using transient upper limb ischemia as the protective stimulus, reduces myocardial injury in patients undergoing CABG surgery. Fifty seven adult patients undergoing elective CABG surgery were randomized to RIPC (n=27) or control (n=30) following induction of anesthesia. RIPC comprised three 5-min cycles of right upper limb ischemia, induced by an automated cuff-inflator placed on the upper arm and inflated to 200 mmHg, with an intervening 5 minutes of reperfusion during which time the cuff was deflated. Serum troponin-T was measured pre-operatively and at 6, 12, 24, 48 and 72 hours post-surgery. Pre-operative troponin-T in all patients was <0.01 μg/L. RIPC significantly reduced serum troponin-T release in patients undergoing elective CABG surgery, at 6, 12, 24 and 48 hours post-surgery, such that the total area under the curve was reduced by 43% with RIPC (20.58±9.58 μg/L over 72 hours in RIPC vs 36.12±26.08 μg/L over 72 hours in control: 95% CI 4.88–26.21 μg/L:P=0.005). This clinical study demonstrates for the first time that remote ischemic preconditioning induced by transient upper limb ischemia reduces myocardial injury in adult patients undergoing elective CABG surgery.