Research on how state legislative term limits affect legislative organization and policy is primarily conjectural, since these limits have been in place for only a short period. However, the effects of retroactive term limits can be analyzed and can yield, with some certainty, the impact of these limits on tenure. Using an earlier study as a model, I develop a cohort analysis to assess how many state legislators currently serving would be affected by a retroactive eight-year term limit. I find that a majority of state legislators both in states that have not adopted term limits and in the 15 states that have adopted limits would be forced out of office. Variation in retention rates is related to chamber, to Squire's opportunity type, and to legislative professionalism, although the last factor does not come into play as heavily in states where term limits already exist.