Objectives: To adapt the Quality Assessment of Diagnostic Accuracy Assessment (QUADAS) to the particular methodological challenges posed by research on '-omics'-based diagnostic tests. Design and methods: We generated new guidelines by appraising the suitability of each criterion from QUADAS to '-omics'-based diagnostic research, and by adding new items that addressed specific sources of error. In addition, we defined four phases in the evaluation of a diagnostic test. Results: Twelve of the 14 criteria from QUADAS were retained in the new tool. The items relating to selection criteria and the description of the test were reformulated, and the criteria about external validation and the availability of clinical data were applied only in studies in the last research phase. Four new items were incorporated to QUADOMICS related to pre-analytical conditions and methods to avoid overfitting. Conclusions: QUADOMICS is an adaptation of QUADAS to the special nature of '-omics'-based diagnostic research. The tool adds new items that assess quality issues specific to this research, and may enhance the application of '-omics'-based discoveries to clinical \and public health practice. © 2008 The Canadian Society of Clinical Chemists.