The deuterium, frequently used stable isotope in isotopic labeling for quantitative proteomics, could deteriorate the accuracy and precision of proteome quantification owing to the retention time shift of deuterated peptides from the hydrogenated counterpart. Herein, we introduce a novel three-plexed peptide ‘di-ethylation’ using only 13C-isotopologues of acetaldehyde and demonstrate that the accuracy and precision of our method in proteome quantification are significantly superior to the conventional deuterium-based di-methylation labeling in both a single shot and multidimensional LC-MS/MS analysis of HeLa proteome. Furthermore, in time-resolved profiling of Xenopus laevis early embryogenesis, our 3-plexed di-ethylation outperformed isobaric labeling approaches in terms of quantification accuracy or number of protein identification, generating >2 times more differentially expressed proteins. Our cost-effective and highly accurate 3-plexed di-ethylation method could contribute to various types of quantitative proteomics applications, in which three of multiplexity would be sufficient.