Objectives: The purpose of this project was to create a measure of safety climate for hospital inpatient care units and to determine the psychometric properties of the measure. Methods: The first version of the measure was derived from published literature. Two rounds of expert review refined that measure. The measure was then pilot tested with 213 RN staff nurses working on 19 units in two hospitals, and administered a second time in one of those hospitals. Results: The Hospital Unit Safety Climate measure contains 33 items measuring 7 dimensions of safety climate. Internal consistency reliability was acceptable for the new measure. This measure has content validity and initial construct validity as indicated by factor analysis and comparative analysis. Early evidence suggests sensitivity and responsiveness. Conclusions: This safety climate measure is a strong alternative to the tools currently available for projects focusing on safety in inpatient units in acute care hospitals. The measure is being used in a national sample of hospitals participating in a study of the working conditions that affect medication accuracy.