Background: Dopamine has been used in patients with cardiac dysfunction for more than five decades. Yet, no systematic review has assessed the effects of dopamine in critically ill patients with cardiac dysfunction. Methods: This systematic review was conducted following The Cochrane Handbook for Systematic Reviews of Interventions. We searched for trials including patients with observed cardiac dysfunction published until 19 April 2018. Risk of bias was evaluated and Trial Sequential Analyses were conducted. The primary outcome was all-cause mortality at longest follow-up. Secondary outcomes were serious adverse events, myocardial infarction, arrhythmias, and renal replacement therapy. We used GRADE to assess the certainty of the evidence. Results: We identified 17 trials randomising 1218 participants. All trials were at high risk of bias and only one trial used placebo. Dopamine compared with any control treatment was not significantly associated with relative risk of mortality (60/457 [13%] vs 90/581 [15%]; RR 0.91; 95% confidence interval 0.68-1.21) or any other patient-centred outcomes. Trial Sequential Analyses of all outcomes showed that there was insufficient information to confirm or reject our anticipated intervention effects. There were also no statistically significant associations for any of the outcomes in subgroup analyses by type of comparator (inactive compared to potentially active), dopamine dose (low compared to moderate dose), or setting (cardiac surgery compared to heart failure). Conclusion: Evidence for dopamine in critically ill patients with cardiac dysfunction is sparse, of low quality, and inconclusive. The use of dopamine for cardiac dysfunction can neither be recommended nor refuted.