Healthcare professionals working in intensive care units (ICUs) are often involved in end-of-life decision-making. No research has been done so far about these processes taking place in Croatian ICUs. The aim of this study was to investigate the perceptions, experiences, and challenges healthcare professionals face when dealing with end-of-life decisions in ICUs in Croatia. A qualitative study was performed using professionally homogenous focus groups of ICU nurses and physicians (45 in total) of diverse professional and clinical backgrounds at three research sites (Zagreb, Rijeka, Split). In total, six institutions at the tertiary level of healthcare were included. The constant comparative analysis method was used in the analysis of the data. Differences were found between the perceptions and experiences of nurses and physicians in relation to end-of-life decisions. Nurses’ perceptions were more focused on the context and features of immediate care, while physicians’ perceptions also included the wider sociocultural context. However, the critical issues these specific professional groups face when dealing with end-of-life decisions seem to overlap. A high variability of practices, both between individual practitioners and between different organizational units, was omnipresent. The lack of adequate legal, professional, and clinical guidelines was commonly expressed as one of the most critical source of difficulties.