Background There exist no recommendations as to how aggregate research results should best be disclosed to long‐term cohort participants. Objective To study the impact of cohort results disclosure documents of various kinds on participants’ satisfaction. Design Randomized study with a 2x2 factorial design. Setting and participants The GENEPSO‐PS cohort is used to study the psychosocial characteristics and preventive behaviour of both BRCA1/2 carriers and non‐carriers; 235 participants wishing to receive ‘information about the survey results’ answered a self‐administered questionnaire. Interventions The impact of providing the following items in addition to a leaflet about aggregate psychosocial research results was investigated (i) an up‐to‐date medical information sheet about BRCA1/2 genetic topics, (ii) a photograph with the names of the researchers. Main outcome measures Satisfaction profiles drawn up using cluster analysis methods. Results Providing additional medical and/or research team information had no significant effect on satisfaction. The patients attributed to the ‘poorly satisfied’ group (n = 60, 25.5%) differed significantly from those in the ‘highly satisfied’ group (n = 51, 21.7%): they were younger [odds ratio (OR) = 0.96, 95% confidence interval (0.92–0.99), P = 0.028], less often had a daughter [OR = 4.87 (1.80–13.20), P = 0.002], had reached a higher educational level [OR = 2.94 (1.24–6.95), P = 0.014] and more frequently carried a BRCA1/2 mutation [OR = 2.73 (1.20–6.23), P = 0.017]. Conclusions This original approach to disclosing research results to cohort participants was welcomed by most of the participants, but less by the more educated and by BRCA1/2 carriers. Although an easily understandable document is necessary, it might also be worth providing some participants with more in‐depth information.