A simple, extractive heptafluoro-n-butyrylation with Extrelut columns was devised to simultaneously measure methamphetamine (MAMP), amphetamine (AMP), 4-hydroxymethamphetamine (HMAMP), and 4-hydroxyamphetamine (HAMP) in biological materials by gas chromatography-mass spectrometry (GC-MS) using 4-methoxymethamphetamine-d5 as the internal standard. Human urine, human whole blood, and porcine skeletal muscle spiked with the stimulant standards were used for evaluating the method. After deproteinization and adjustment of the pH to 12.6, the sample was applied to an Extrelut column. Using the present method, AMP, MAMP, and HMAMP could be determined in an actual forensic case study.