Human milk (HM) and infant formula (IF) protein digestibility has been rarely studied in vivo with no value for tryptophan. The study aimed to measure their standardised ileal digestibility (SID), i.e. after endogenous Nitrogen loss correction, using Yucatan mini-piglets as infant model. Nineteen days-old piglets received HM (n=7, duration=6 days), IF (n=8, duration=6 days) or protein-free (n=6, duration=3 days; endogenous Nitrogen loss determination) diets with Cobalt-EDTA (indigestible marker). Diets were hourly administrated during 6h before euthanasia and digesta collection. SID of Nitrogen and amino acids (AAs) were determined. Differences between groups were assessed using an ANOVA. AAs and Nitrogen contents were similar between HM and IF diets, except lower lysine content in HM (-32%). Endogenous losses corrected digestibility values of 6 to 14%. SID of total Nitrogen was significantly lower for HM (91.3±1.2% vs. 98.0±0.9%), but SID of AA Nitrogen was not significantly different (97.5±0.5%). HM and IF had similar SID (p>0.05) for most AAs, including tryptophan (96.2±0.5%, p=0.07), except for a few AAs (Lys, Phe, Thr, Ala, Pro), slightly but significantly differing. Overall, this indicates that a larger proportion of non-protein Nitrogen is transferred to the microbiota with HM, which is likely of physiological relevance, although not yet considered in IF production.