Critical thinking abilities are required in nursing practice due to the acuity of ill patients and the complexity of the current health care environment. Nursing students learn to think critically as they progress through a nursing curriculum. Research has not consistently demonstrated the differences in critical thinking abilities in students at varying levels of nursing curricula. The purpose of this cross-sectional study is to compare critical thinking abilities in sophomore and senior nursing students. This study is a partial replication of Profetto-McGrath’s (2002) research. Guided by a conceptual framework by McCarthy, Schuster, Zehr and McDougal (1999), this study samples 228 nursing students at a Midwestern university. Participants will be in the second and last years of the curriculum. Institutional Review Board approval will be obtained. Participants will respond to the California Critical Thinking Skills Test (CCTST) (Facione, 2000) and the California Critical Thinking Disposition Inventory (CCTDI) (Facione, 2001). Results of the study will add nurse educators’ understanding of critical thinking abilities in students at the beginning and end of a curriculum.