The aim of this study was to assess the impact of a standardized patient information booklet on decisions women make about genetic testing. This French national multi-centre survey included all women with cancer to whom genetic testing for BRCA1/2 mutation had been proposed. The control group was surveyed before the booklet became available (n = 263), and the experimental group, after being given it personally (n = 297). After multivariate adjustment, the booklet had a positive impact on satisfaction with the information provided (Odds ratio (OR) = 2.9; 99% confidence interval (CI) = 1.7-5.0; P = 0.001), decreased the decisional conflicts due to lack of information (OR = 1.9; 99% CI = 1.1-3.3; P = 0.002), and had a marginal impact on knowledge (R2-gain = 3%; P = 0.001). The women in the experimental group decided more frequently to undergo testing (99% vs. 95%; P = 0.009). In addition to a consultation providing more tailored information, a standardized written document improved the decision-making process involved in giving informed consent to genetic testing.