The Orientation to Life Questionnaire (SOC-29) for the measurement of the sense of coherence, the key construct of a popular theory by Antonovsky, has no univocally established construct validity. The aim of the study was to explore differential and convergent aspects of its construct validity. An attempt was made to determine the relationships between the SOC-29 Questionnaire on the one hand and, on the other hand, measures of optimism, generalized self-efficacy, trait anxiety, neuroticism, and depression. The results indicate that one common factor explains a significant proportion of variance of all the instruments studied, which suggests that they are indicators of the same higher-order construct. A particularly strong relationship was found between SOC and both trait anxiety and neuroticism, so redundancy of these three measures seems to be highly probable. Since 26% unique variance of the sense of coherence was noted, further research is needed to establish discriminative validity of the instrument (at present rather doubtful).