I am not an expert on this, but the BIG question is which interface were you using to MySQL. If you used a MySQL-specific one, then you are going to need to change EVERY call to a different library that was designed to use SQLite (directly or generically). If you used a generic library that supports both MySQL and SQLite, then you might just need to change your connection call. A bit more likely there will be some calls that behave enough different between the two back-ends that you need to make other changes, but this path would be much simpler. As was else mentioned, this is really a topic for a PHP database group, but come here if specific operations in SQLite seem to be a problem.