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A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether dialysis-dependent patients with upper limb arterio-venous fistulae (AVFs) undergoing coronary artery bypass grafting should avoid having ipsilateral in situ internal mammary artery (IMA) grafts. A literature search performed yielded 28 peer reviewed articles, of which 21 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The papers identified included 478 patients, of whom 219 had in situ IMA grafts with ipsilateral upper limb arterio-venous fistulae. There was a substantial variation between the papers, from single case reports to small retrospective cohort studies, but no randomized, controlled trials. The largest retrospective study included 155 patients and followed up for up to 5 years. Methods used to determine coronary steal included clinical assessment, electrocardiogram or echocardiographic changes, Doppler ultrasound of mammary arteries and angiography. The aggregate evidence suggested that 61 of the 219 patients with ipsilateral IMA grafts developed some clinical or physiological evidence of malperfusion during the use of the AVFs for dialysis. Comparisons with the contralateral IMA suggested that 27 of the 61 patients suffered similar problems when dialysis was applied. A number of studies used controls, including in situ right internal mammary artery (RIMA) flow and patients not on dialysis. In total, 32 patients had their in situ RIMA flow measurements studied, of which none showed any statistically significant flow alteration. While further strong evidence to demonstrate long-term outcomes is required, we recommend the avoidance, where possible, of ipsilateral in situ IMA grafts in patients with an upper limb AVF. There is sufficient experimental and anecdotal evidence to suggest that steal occurs and that in some patients, this has clinical implications on both morbidity and mortality. In this scenario, the use of the contralateral mammary is strongly advocated to maximize the patency of grafts in an already high-risk population.