Valid and reliable instruments are needed to measure how family members perceive support from nurses when a family member is experiencing serious illness. The purpose of this article is to describe the development and psychometric testing of a new instrument, the Iceland-Family Perceived Support Questionnaire (ICE-FPSQ). The concepts in the original version of the ICE-FPSQ (suggesting 24 items and 4 categories) were developed from the Calgary Family Intervention Model. In the first phase of the instrument construction, 179 family members answered the original ICE-FPSQ, and 236 answered the questionnaire in the second phase of testing. Principal Component Analysis (PCA) reduced the original questionnaire to 21 items. Cronbach's a = .959 explained 68% of the total variance, with three factors emerging: (a) emotional support (a = .925), (b) recognition of families' strengths (a = .926), and (c) cognitive support (a = .841). Confirmatory Factor Analyses (CFA) resulted in a final version of the questionnaire containing 14 items with total alpha of .961 and two factors: (a) cognitive support (a = .881) and (b) emotional support (a = .952). The instrument measures family's perceptions of support provided by nurses and will be helpful in examining the usefulness of family nursing interventions.