The field of critical care medicine began to flourish only within the last 40 years, yet it provides some of the best examples of collaborative pharmacy practice models and evidence for the value of pharmacist involvement in interdisciplinary practice. This collaborative approach is fostered by critical care organizations that have elected pharmacists into leadership positions and recognized pharmacists through various honors. There is substantial literature to support the value of the critical care pharmacist as a member of an interdisciplinary intensive care unit (ICU) team, particularly in terms of patient safety. Furthermore, a number of economic investigations have demonstrated cost savings or cost avoidance with pharmacist involvement. As the published evidence supporting pharmacist involvement in patient care activities in the ICU setting has increased, surveys have demonstrated an increase in the percentage of pharmacists performing clinical activities. In addition, substantial support of pharmacists has been provided by other clinicians, safety officers, and administrative personnel who have been involved with the initiation and expansion of critical care pharmacy services in their own institutions. Although there is still room for improvement in the range of pharmacist involvement, particularly with respect to interdisciplinary activities related to education and scholarship, pharmacists have become essential members of interdisciplinary care teams in ICU settings.