Easy to use, interactive, and platform independent WWW-based tools are ideal for applications in chemical information processing. In Crop Protection Division of CIBA-GEIGY we developed a WWW-based chemical information system, which enables easy retrieval of molecules with corresponding data from corporate databases, on-line calculation of physico-chemical molecular properties, generation of molecular images in various modes, similarity searching and simple QSAR analysis. An integral part of this system is a WWW-based molecular editor.The editor consists of three modules:* a graphical user interface written in HTML with several radio buttons to choose desired action and a clickable map which serves as a drawing area* cgi-bin PERL program which processes the users input, and* a program written in C which performs the actual construction of the molecule and returns the molecular image in GIF format.The molecular editor enables fast construction of organic molecules by adding, connecting, or deleting atoms, bonds, rings and functional groups. The use of the editor is very simple, and users are able to construct even complex organic molecules without any training.