The aim of the study was to investigate the use of the Functional Capacity Scale (FCS) to measure functional outcome of patients who had undergone surgical removal of an intracranial aneurysm in the early postoperative period. Reliability and validity of the tool were tested as well as its utility in nursing practice. The study included 120 patients, operated on for intracranial aneurysm. Phase I included 23 patients. Reliability of FCS and the amount of time used for the assessment were tested using observation and direct measurement methods. Phase II included 97 patients, and the tool was administered along with standard outcome assessment tools (Barthel Index, Functional Index “Repty,” Glasgow Outcome Score, and Rankin Scale) to determine concurrent validity. Kendall’s coefficients of concordance (W) between particular care markers of FCS ranged from 0.910 to 1.000. Mean amount of time used for assessment was 90 seconds. Differences between time used for measurements by individual examiners were insignificant (p > .05). Correlation of FCS with the following scales was statistically significant: Functional Index “Repty” (p < .001), Glasgow Outcome Score (p < .01), Rankin Scale (p < .01), and Barthel Index (p < .001). The FCS appears to be a reliable, valid, and practical assessment tool for neuroscience nurses to use with patients who have undergone surgical removal of an intracranial aneurysm.