Spiritual care is increasingly being recognized as an integral aspect of nursing practice. The aim of this study was to develop a new instrument, Spiritual Care Needs Inventory (SCNI), for measuring spiritual care needs in acute care hospital patients with different religious beliefs. The 21-item instrument was completed by 1,351 adult acute care patients recruited from a medical center in Taiwan. Principal components analysis of the SCNI revealed two components, (a) meaning and hope and (b) caring and respect, which together accounted for 66.2% of the total variance. The internal consistency measures for the two components were 0.96 and 0.91, respectively. Furthermore, younger age, female sex, Christian religion, and regularly attending religious activities had significantly higher mean total scores in both components. The SCNI was found to be a simple instrument with excellent internal consistency for measuring the spiritual care needs in acute care hospital patients.