1582 Background: Predictive genetic testing for familial cancer may alert people to highly elevated risk prior to disease onset. Genetic test reporting has been shown to improve uptake of prophylactic screening and procedures, but whether test reporting also promotes increased performance of primary preventive behavior is unknown. Methods: Unaffected adult participants ( N= 124) from high-risk melanoma families, ages 16-69 (mean = 35.24, 52% men) were enrolled. Participants from families that carried a CDKN2A/p16 mutation received a personal genetic test result and counseling about management recommendations whereas control participants from families without a CDKN2A/16 mutation received equivalent counseling and management recommendations based on family history alone. Photoprotection outcomes were compared between CDKN2A/p16 participants (31 carriers, 44 noncarriers) and the no-test control group ( n= 49), allowing the effects of receiving a genetic test result to be distinguished from the effects of counseling alone. Assessments were seasonally timed to capture tanning during the summer months. Melanin Index (MI) scores, measures of skin tanning obtained through reflectance spectroscopy, were assessed at the dorsal wrist and face. Tanning of the dorsal wrist and face were calculated by subtracting baseline MI scores at an unexposed site on the same individual. Results: Multilevel model analyses examined changes in tanning over time while controlling for clinician-rated skin type, age, gender, date of assessment, and group differences in phenotypic factors and family medical history. Participants who received positive test results were significantly less tan at the wrist one year after their previous summer baseline ( b= -.11, p< .001). No-test controls and noncarriers had no change in tanning. The magnitude of decrease in tanning measurements observed among CDKN2A/ p16 carriers approximated one skin type. Facial tanning did not differ from baseline for any group. Conclusions: A positive melanoma genetic test result promotes reduced UVR exposure. Future research should examine why positive genetic test reports were more motivating to patients than equivalent counseling based on family history.