Different kinds of yogurt contain different percentages of proteins. However, do they also contain different types of proteins? To answer to this question, we investigated the protein pattern in the soluble fraction of various yogurts. We found that many yogurts contain mostly two main bands: a ~20 kDa band and a ~15 kDa band. Proteomics analysis of these two bands led us to conclude that the 20 kDa band corresponds to lactoglobulin isoforms and the 15 kDa band corresponds to casein isoforms.