An upper-division undergraduate- or graduate-level laboratory experiment, challenging students to identify bovine serum albumin, equine myoglobin, bovine calmodulin, and bovine cytochrome c, uses four methods of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS): linear positive, in-source decay, peptide mass fingerprint, and postsource decay. Individual hands-on experience with each method is provided in a three week experiment. The importance of sequencing proteins/peptides when identifying proteomic targets using MALDI-TOF MS is emphasized.