- This paper presents an overview on qualification and certification of tools used in the phases of the safety lifecycle for safety-critical applications, either for development or for verification and validation. Software development tools are widely used in the development of safety-critical software systems. More verification and validation procedures will be automated by software tools to reduce time consuming manual testing. The impact of software tools on functional safety is discussed. Based on normative regulations like IEC 61508 and ISO DIS 26262 different approaches for tool qualification and certification are presented.