The aim of this study was to quantify the reasons and opinions of patients who reported adverse drug reactions (ADRs) in the Netherlands to a pharmacovigilance centre. A web-based questionnaire was sent to 1370 patients who had previously reported an ADR to a pharmacovigilance centre. The data were analysed using descriptive statistics, chi(2) tests and Spearman's correlation coefficients. The response rate was 76.5% after one reminder. The main reasons for patients to report ADRs were to share their experiences (89% agreed or strongly agreed), the severity of the reaction (86% agreed or strongly agreed to the statement), worries about their own situation (63.2% agreed or strongly agreed) and the fact the ADR was not mentioned in the patient information leaflet (57.6% agreed or strongly agreed). Of the patient-responders, 93.8% shared the opinion that reporting an ADR can prevent harm to other people, 97.9% believed that reporting contributes to research and knowledge, 90.7% stated that they felt responsible for reporting an ADR and 92.5% stated that they will report a possible ADR once again in the future. The main motives for patients to report their ADRs to a pharmacovigilance centre were the severity of the ADR and their need to share experiences. The high level of response to the questionnaire shows that patients are involved when it comes to ADRs and that they are also willing to share their motivations for and opinions about the reporting of ADRs with a pharmacovigilance centre.