The emergence of companion diagnostic devices has been spurred by drug discovery and development efforts towards targeted therapies, particularly in oncology. Companion diagnostics and their corresponding therapeutics are often codeveloped, or developed in parallel, to ensure the safe and effective use of the products. The regulatory framework for companion diagnostics has gradually evolved as a result of the essential role of diagnostic tests to identify the intended population for a corresponding treatment. Here, we describe the current regulatory model for companion diagnostics in the US and outline key strategies for a successful codevelopment program from the device perspective. We also discuss how technological advances and changes in clinical management may challenge the regulatory model in the future.