Proteomic and transcriptomic data are often analyzed side-by-side to yield complementary information. To minimize variation between the proteomic and transcriptomic datasets, it is essential to be able to "freeze" the proteins and mRNA to prevent any further modification or degradation during the sample preparation. RNA protection agents like RNAprotect® offer a simple way to block any modifications and are easy to use. To avoid the introduction of variations from parallel experiments for proteomics and transcriptomics, it is desirable to develop a quick and easy sample preparation method to extract proteins and RNA simultaneously from the same sample. The described method using RNAprotect® Cell Reagent (Qiagen, Belgium) can minimize variances due to multiple sampling and help increase the throughput in the analysis of large measurement cohorts. By adding RNAprotect®, the RNA and proteins are rapidly extracted and stabilized for months before the sample can be further processed for the actual measurement. The method is widely suitable for any cell culture experimental setups, including cells growing on membrane inserts. We developed a workflow for the rapid measurement of proteomic and transcriptomic data, which allows the deep analysis of proteome and transcriptome from the same sample.