Purpose: Patients in the intensive care unit (ICU) are often transfused with red blood cells (RBC). During storage, the RBCs and storage medium undergo changes, which may have clinical consequences. Several trials now have assessed these consequences, and we reviewed the present evidence on the effects of shorter versus longer storage time of transfused RBCs on outcomes in ICU patients. Methods: We conducted a systematic review with meta-analyses and trial sequential analyses (TSA) of randomised clinical trials including adult ICU patients transfused with fresher versus older or standard issue blood. Results: We included seven trials with a total of 18,283 randomised ICU patients; two trials of 7504 patients were judged to have low risk of bias. We observed no effects of fresher versus older blood on death (relative risk 1.04, 95% confidence interval (CI) 0.97–1.11; 7349 patients; TSA-adjusted CI 0.93–1.15), adverse events (1.26, 0.76–2.09; 7332 patients; TSA-adjusted CI 0.16–9.87) or post-transfusion infections (1.07, 0.96–1.20; 7332 patients; TSA-adjusted CI 0.90–1.27). The results were unchanged by including trials with high risk of bias. TSA confirmed the results and the required information size was reached for mortality for a relative risk change of 20%. Conclusions: We may be able to reject a clinically meaningful effect of RBC storage time on mortality in transfused adult ICU patients as our trial sequential analyses reject a 10% relative risk change in death when comparing fresher versus older blood for transfusion.