This study examined the impact of overreporting on the validity of Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) substantive scale scores by comparing correlations with relevant external criteria (i.e., validity coefficients) of individuals who completed the instrument under instructions to (a) feign psychopathology or (b) feign somatic complaints, with validity findings for a control group of individuals who completed the MMPI-2-RF under standard instructions. Validity coefficients for MMPI-2-RF substantive scale scores were much weaker for feigners than for controls. The authors also found mean profiles to be more elevated for feigners than for controls. Effects were more extreme for psychopathology feigners than for somatic feigners. The results demonstrate the detrimental effect that overreporting psychopathology or somatic problems has on the validity of MMPI-2-RF scale scores. The findings illustrate the need for validity indices in self-report measures of personality and psychopathology. (Contains 10 tables and 1 note.)