As of the summer of 1998, more than 520 sexual predators had been committed in Arizona, California, Florida, Illinois, Iowa, Kansas, Minnesota, New Jersey, North Dakota, South Carolina, Washington, and Wisconsin. Sexual predator laws in these States conform in many aspects: commitment follows a criminal sentence; laws target repeat sex offenders; and evidence regarding the individual's likelihood of future violence is central to decision making. Several differences exist among sexual predator laws in the 12 States. For example, most States require the beyond a reasonable doubt standard used in criminal proceedings as the burden of proof for commitment, while other States use the lower standard of clear and convincing evidence. A few States specifically provide that juveniles are eligible for commitment, while other States stipulate that petitions can be filed on persons who are 18 years of age or older. California's law calls for a time-limited confinement of 2 years, while the remaining 11 States authorize indeterminate commitment periods. In 1998, legislative proposals for postrelease confinement of sexual predators were introduced in at least 21 States. An appendix contains information on Washington State's End of Sentence Review Committee. 3 references, 3 tables, and 4 figures