The current system of risk assessment of chemicals is complex, very resource-intensive and extremely time-consuming. Because of this, there is a great need to modernize this process. However, this is not feasible without alternative, integrated testing strategies in which chemical characteristics are used to more advantage and where costly and time consuming animal tests are replaced to a large extent by more rapid, cheap and ethically less controversial methods. This is particularly needed for reproductive toxicity testing of chemicals. Reproductive toxicity is important to assess both human and environmental toxicity and uses the most animals in toxicity testing. Unfortunately, there are very few alternative methods. ChemScreen aims to fill this gap and place the tests in a more general innovative animal-free testing strategy. For this, we will generate a simple rapid screening system, which aims at widespread implementation within the tight time schedule of the REACH program. It will be a flexible tool that can be adapted and used for applications beyond the scope of REACH and in the post-REACH period. It will use in silico methods for prescreening chemicals for all relevant toxic effects. When found positive, this will be followed by further in silico and in vitro tests, most of which are available already. To fill the gap of suitable alternative methods for reproductive toxicity testing we will use a novel high throughput approach combining in silico/in vitro methods. In this approach we will combine knowledge of critical processes affected by reproductive toxicants with knowledge on the mechanistic basis of such effects. Straightforward data interpretation and decision trees will be developed in which all information on the potential toxicity of a chemical is considered. In this way we will provide a cost-effective means to generate a basic set of data on toxicological properties of chemicals and a decision tool to assess if further testing of chemicals is required.