Two hundred patients with severe and/or life-threatening disease were recruited form the NIH Clinical Center and participated in the validation of the NIH-HEALS, which included exploratory factor analysis, principal component analysis, reliability, convergent validity, and divergent validity analyses. Item-reducing principal components analysis and internal consistency and split-half reliability demonstrated excellent internal consistency and split-half reliability (Cronbach's alpha = 0.89, split-half reliability = 0.95). Exploratory factor analysis revealed a three-factor structure, namely Connection (including religious, spiritual, and interpersonal), Reflection & Introspection, and Trust & Acceptance. Seven items were not retained. Convergent and divergent validity of 35-item NIH-HEALS against other validated measures of healing and spirituality provided strong evidence for its validity. As predicted, the Healed factor of the Self-Integration Scale (SIS), and Meaning, Peace, and Faith factors of the Functional Assessment of Chronic Illness Therapy-Spiritual Well-Being-12 Scale (FACIT-SP12) were all positively and significantly correlated with the NIH-HEALS and its three factors. Divergent validity was also confirmed by the significant negative correlation between the NIH-HEALS and the Codependent factor on the SIS. Confirmatory Factor Analyses revealed good model fit by GFI (0.96), adjusted GFI (0.95), SRMR (0.077), and RMSEA (0.065), supporting the use of the NIH-HEALS with 35 items.