This post is about the business rules engine Drools in combination with Scala . I have recently started to become interested in business rules engines and I am eager to find promising solutions in combination with the powerful programming language Scala. In this post I introduce the concept of business rules engines and the main motivations to use one. As a follow up in the post, I give a short overview of the rules engine Drools. In an example which can be found on Github, I show how Drools can be used in combination with Scala, explaining various implementation details. I also describe the problems I encountered by using Drools with Scala and how I fixed them.