The Occupational Stress Indicator (OSI) is a popular instrument for the diagnosis of stress and stress-related personality and outcome variables. However, one weakness of the OSI was the low reliability of some of its scales. This paper describes in a series of four studies improvements of the reliabilities of most of the scales of the Dutch version of the OSI. All new scales were tested for unidimensionality. Compared to the original OSI, the personality scales (type A, locus of control, and coping styles) have been changed completely and nearly all original items were replaced. The other scales are revisions of the original OSI, with some items being deleted, rewritten, or added. A new scale for satisfaction with pay was included. All but two of the revised scales now show sufficient reliabilities and unidimensionality. This revision led us to suggest two versions of the OSI: an elaborate version with 28 scales and 188 items, and an abridged version with 15 scales and 94 items.