Data collection via Internet is usually performed with an HTML/CGI combination, which has a lot of disadvantages, most important the lack of security features. We therefore have developed a system written entirely in Java, which implements a true client/server application based on TCP/IP. The documents are created using a multi-lingual data dictionary, and the used GUI components are able to perform plausibility checks, which improves quality of the data. The system is designed to be easily extensible so that it can be used in almost any kind of clinical trials. It is based on a three-tier model where client requests are handled and monitored by an application server. We will describe this system and it's implementation and compare it to the HTML/CGI approach. Of special interest are security features, which are possible through the use of Java.