Since its appearance in 1974, the Snyder Self-Monitoring Scale has been employed in research dealing with self-presentation, attribution, and attitude expression. The Scale was developed to measure the degree to which people are concerned with the social appropriateness of their behavior, are aware of relevant social cues, and regulate their expressive behavior. Examination of the scale items, however, suggests that not all three aspects of self-monitoring are tapped equally, and that some items do not clearly represent any aspect of self-monitoring. The Self-Monitoring Scale was administered to 237 undergraduates and factor analyzed to determine whether it measures a unitary construct. A principal axis analysis with varimax rotation yielded three major factors: Public Impression Management, Acting, and Social Insecurity. Of the three, only the first factor was clearly central to the construct of self-monitoring. Results suggest that the multidimensionality of the scale makes its use in classifying subjects as high versus low self-monitors questionable and may result in equivocal research findings. (Author/HLM)