In the present study, the equivalence of paper and pencil assessment versus computer assessment of two self-administered questionnaires was investigated by means of a randomized cross-over design. Therefore, 105 out-patients with diabetes were invited to participate; 76 patients completed both the computer and the paper and pencil version of the Well-being Questionnaire (WBQ) and the Diabetes Treatment Satisfaction Questionnaire (DTSQ) in a randomized order, with a mean interval of 7 days. The scales showed high test-retest correlations and the means, dispersions, kurtosis and skewness were found to be approximately the same in both versions. In both modes of assessment, the depression and the energy scale proved to be sensitive for carry-over effects, resulting in better well-being scores at the second measurement. Almost all subjects reported that using the personal computer in the realization of a questionnaire was easy. It is concluded that the paper and pencil and the computerized versions of the WBQ and DTSQ can be considered equivalent. Therefore, the norms and cut-off scores obtained from paper and pencil assessments can be used in computerized versions of the WBQ and DTSQ and vice versa.