The purpose of this study was to consider the application of sex offender risk-assessment measures on offenders with adult or child victims, and to compare risk levels between two referral agencies -- the Probation Service and a United Kingdom Regional Secure Unit (RSU). Estimates of risks were completed on 139 sex offenders using risk assessments for sexual offenders. The risk assessment measures were the Structured Anchored Clinical Judgment Scale (SACJ), the Rapid Risk Assessment for Sex Offense Recidivism (RRASOR), Static-99, the Risk Matrix 2000-Sexual/Violence, and the Sexual Violence Risk-20 (SVR-20). The results show that, in spite of strong concurrent validity between the scales, classifications of risk varied. Levels of risk of sexual offenders against children and adults ranged from 7 percent low risk to 62 percent high risk and 0 percent low risk to 93 percent high risk, respectively. Depending on the risk assessment instrument being used, 85.1 percent and 92.6 percent of offenders with adult victims were considered medium-high to high risk using Static-99 and SACJ-Min, respectively, compared with 83.9 percent of offenders with child victims considered low to medium-low risk using the RM2000/S. Trends and differences in risk between measures were found when considering the referral agency where levels of risk for RSU and Probation Service samples ranged from 1 percent low risk to 66 percent high risk and 8 percent low risk to 70 percent high risk, respectively. Sex offenders supervised by the Probation Service scored significantly higher on Static-99 and RM2000/S than did sex offenders referred to a RSU for a treatment assessment. Levels and categories of risk between instruments appear inconsistent and vary depending on which measure is being used. 6 tables, 1 note, 76 references