Prolog Server Pages (PSP) is a scripting language, based on Prolog, than can be embedded in HTML documents. To run PSP applications one needs a web server, a web browser and a PSP interpreter. The code is executed, by the interpreter, on the server-side (web server) and the output (together with the html code in witch the PSP code is embedded) is sent to the client-side (browser). The current implementation supports Apache Web Server. We implemented an Apache web server module that handles PSP files, and sends the result (an html document) to the client. PSP supports both GET and POST http requests. It also provides methods for working with http cookies. In the spirit of Open Source movement we chose not to implement from ground a Prolog compiler, but rather to use an existing product. We chose SWIProlog as the Prolog backend of our application. PSP is open source software, distributed under the LGPL license.