The study objective was to evaluate the psychometric properties of a decisional conflict scale (DCS) that elicits: 1) health-care consumers' uncertainty in making a health-related decision; 2) the factors contributing to the uncertainty; and 3) health-care consumers' perceived effective decision making. The DCS was developed in response to the lack of instruments available to evaluate health-care-consumer decision aids and to tailor decision-supporting interventions to particular consumer needs. The scale was evaluated with 909 individuals deciding about influenza immunization or breast cancer screening. A subsample of respondents was retested two weeks later. The test-retest reliability coefficient was 0.81. Internal consistency coefficients ranged from 0.78 to 0.92. The DCS discriminated significantly (p < 0.0002) between those who had strong intentions either to accept or to decline invitations to receive influenza vaccine or breast cancer screening and those whose intentions were uncertain. The scale also discriminated significantly (p < 0.0002) between those who accepted or rejected immunization and those who delayed their decisions to be immunized. There was a weak inverse correlation (r = -0.16, p < 0.05) between the DCS and knowledge test scores. The psychometric properties of the scale are acceptable. It is feasible and easy to administer. Evaluations of responsiveness to change and validation with more difficult decisions are warranted.