Over-reporting of posttraumatic stress disorder (PTSD) symptoms has been observed in some cases, following a motor vehicle accident (MVA). It has been suggested, however, that these are cases of underdiagnoses in primary care settings. The current study focused on people with PTSD in primary care settings who experienced an MVA and do not seek psychiatric help.In the over 3000 patient registry of a primary care clinic, 174 people who experienced an MVA (PE-MVA) were identified. The final sample included 45 PE-MVA, who were administered the Clinician-Administered Posttraumatic Stress Disorder Scale (CAPS-2), and completed the Injury Severity Scale (ISS) and the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) content scales.PE-MVA with PTSD reported more psychopathology on both MMPI-2 and CAPS-2 than those without PTSD. Severity of injury, measured by the ISS, did not differ significantly between the two PE-MVA groups. The significant differences between the PE-MVA with PTSD and those without PTSD disappeared after adjusting for the covariates of bias scales [Infrequency (F) and Fake Bad (FBS)] in MMPI-2, but not in CAPS-2.The results suggest that in primary care settings, PE-MVA with PTSD who do not seek psychiatric help, over-report psychiatric and somatic symptoms. In a personal injury setting the F scale of the MMPI-2 showed less sensitivity to exaggerated somatic symptoms than the FBS scale. Bias scales of PE-MVA with PTSD are major contributors to the elevation of the MMPI-2 scores but not the CAPS-2 score.