The demand for intensive care services is growing, and the cost of these services is increasing, with newer technologies consuming larger portions of the health care budget. We contend that both the costs and benefits of interventions must be considered to truly understand their value in critical care. Economic evaluations provide an explicit framework to compare the costs and benefits of an intervention. If these factors are not considered together, decisions may be made that do not result in the most efficient use of constrained resources. Despite limitations arising from variations in economic evaluation methodology, logistical complexity and problems of generalisability, the Australian trial environment provides an ideal opportunity to obtain robust economic data to help decision-making. Here, we outline the rationale for conducting economic evaluations in the critical care setting and argue that these evaluations need to be routinely incorporated into all large-scale clinical trials.