The in vivo metabolism of 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT), a psychoactive tryptamine analog, was studied in rat. Male Wistar rats were administered 10 mg/kg 5-MeO-DIPT hydrochloride orally, and urinary fractions were collected. After enzymatic hydrolysis, the metabolites were extracted by liquid-liquid extraction and analyzed by gas chromatography/mass spectrometry. 5-Methoxy-N-isopropyltryptamine, 5-hydroxy-N,N-diisopropyltryptamine (5-OH-DIPT), 5-hydroxy-N-isopropyltryptamine, and 5-methoxyindole-3-acetic acid were identified as 5-MeO-DIPT metabolites. By quantitative analysis using high-performance liquid chromatography, it was revealed that 5-OH-DIPT was the main metabolite of 5-MeO-DIPT in rat, comprising 20.5% of the dose administered. On the other hand, only 0.8% of 5-MeO-DIPT administered was excreted into the urine in its original form.