The Turkish Pharmaceutical Manufacturers Association-Ilaç Endüstrisi Isverenler Sendikasi (IEIS) set guidelines for pharmaceutical companies when designing their websites in 2003. The objective of this study is to evaluate whether pharmaceutical company websites comply with these guidelines. The list of all the national and international pharmaceutical companies active in Turkey is obtained from Farmalist Vademecum. We evaluated each site in terms of availability of drug advertisement, mail address, e-mail address, telephone number, fax number, update information, indication of target group, links, references, information, appropriate content for the intended target group, disclaimer stating the given information is only for health care professionals, disclaimer stating the given information cannot replace a health care professional, responsible body for the website design. The search was done throughout February 2005. We used x(2) test and Fisher's exact x(2) tests for statistical analysis. Of the 82 pharmaceutical companies active in Turkey, 51 had a website eligible for evaluation. Of the 51 companies, 34 (66.7%) were national and 17 (33.3%) were international. Eighteen companies had drug advertisement on the home page of their websites (64.7%). Of the total companies majority had mail address (89.2%); telephone number (89.2%); fax number (84.3%); links (66.7%); and appropriate content for the health care professionals (62.7%). The frequency of having update information and a separate pharmacist/physician information part was higher among international pharmaceutical company websites compared to the national ones. These differences were statistically significant (p < 0.05). As a result of the evaluation, the majority of the pharmaceutical companies failed to comply wholly with the guidelines set by IEIS when designing their website on the Internet.