A patient’s trusting attitude towards technology used in their medical care may be a predictor of acceptance or rejection of the technology and, by extension, the physician. The aim of this study was to rigorously determine the validity of an instrument for measuring patients’ trust in medical technology. Instrument validity was established based on a framework, which included test and data evidence for validity assessment. The framework for validity assessment evaluates the instrument on content, substantive, structural, generalizability, external and consequential aspects of validity. The results of the current study show that the instrument is reliable and valid for assessing a patient’s trust in obstetric medical technology.