The invention provides microarrays comprising a plurality of frozen tissues and/or cell samples and methods of preparing and using the same. By using frozen samples, the microarrays provide optimal samples from which to detect the expression of both nucleic acids (e.g., mRNAs) and proteins in high throughput parallel analyses. The microarrays enable gene identification, molecular profiling, selection of promising drug targets, sorting and prioritizing of expressed sequence array data, and the identification of abnormal physiological processes associated with disease.