The smartphone is an increasingly widespread technological vehicle for general health and psychological health promotion, evaluation, education, and sometimes intervention. However, the psychometric performance of behavioral health screening measures has not been commonly evaluated for the new, small-format, touch-screen medium. Before mobile-based applications for behavioral health screening can be disseminated confidently, the reliability and the validity of measures administered by the smartphone must be evaluated. We compared psychometric properties (i.e., internal consistency and test-retest reliability) of seven behavioral health measures completed on paper, a computer, and an iPhone by 45 army soldiers. The results showed the internal consistencies of the smartphone-delivered measures to be equivalent and very high across all three modalities and the test-retest reliability of the iPhone measures also to be very high. Furthermore, completion of the behavioral screening measures by the iPhone was highly preferred over the other modalities and was reported to be easy and convenient. Our findings help corroborate the use of smartphones and other small mobile devices for behavioral health screening.