There is increasing use of the Internet for the transfer and sharing of medical information. Opportunities to pilot surveys online are now also available. An online HTML questionnaire allowed us to pilot a questionnaire about functional ability and the use of health services in Rett syndrome, a rare neurological disorder. Subscribers to a list server completed the online questionnaire and returned data by CGI script-formatted e-mail. Text boxes were provided for open-ended questions. Eighty-six questionnaires were returned from 224 subscribers with 76% returned within the first week. Almost all respondents were Caucasian, well educated and English speaking. The issue of selection bias and the need for mechanisms to validate the diagnosis are important considerations in any research facilitated through the Internet. However, we were able to contact an otherwise inaccessible group in a fast and cost-efficient manner and effectively pilot our survey without tapping into our own study population.