Based on self-regulation and self-efficacy theories, the Cancer Behavior Inventory (CBI; Heitzmann et al., 2011; Merluzzi & Martinez Sanchez, 1997; Merluzzi, Nairn, Hegde, Martinez Sanchez, & Dunn, 2001) was developed as a measure of self-efficacy strategies for coping with cancer. In the latest revision, CBI-V3.0, a number of psychometric and empirical advances were made: (a) the reading level was reduced to 6th-grade level; (b) individual interviews and focus groups were used to revise items; (c) a new spiritual coping subscale was added; (d) data were collected from 4 samples (total N = 1,405) to conduct an exploratory factor analysis with targeted rotation, 2 confirmatory factor analyses, and differential item functioning; (e) item trimming was used to reduce the total number to 27; (f) internal consistency and test–retest reliability were computed; and (g) extensive validity testing was conducted. The results, which build upon the strengths of prior versions, confirm a structurally and psychometrically sound and unbiased measure of self-efficacy strategies for coping with cancer with a reduced number of items for ease of administration. The factors include Maintaining Activity and Independence, Seeking and Understanding Medical Information, Emotion Regulation, Coping With Treatment Related Side Effects, Accepting Cancer/Maintaining a Positive Attitude, Seeking Social Support, and Using Spiritual Coping. Internal consistency (α = .946), test–retest reliability (r = .890; 4 months), and validity coefficients with a variety of relevant measures indicated strong psychometric properties. The new 27-item CBI-V3.0 has both research utility and clinical utility as a screening and treatment-planning measure of self-efficacy strategies for coping with cancer.