Alkylresorcinols (AR) have been established as short/medium-term biomarkers for whole grain (WG) wheat and rye intake; and AR metabolites, 3,5-dihydroxybenzoic acid and 3-(3,5-dihydroxyphenyl)-propanoic acid, have been suggested as complementary biomarkers to AR. The present study examined the medium-term reproducibility and relative validity of urinary AR metabolites as biomarkers for WG and cereal fibre intake. A total of sixty-six free-living Swedes completed 3 d weighed food records and provided single 24 h urine collections and morning urine spot samples on two occasions, 2-3 months apart. The medium-term reproducibility of urinary AR metabolites was moderate when assessed in 24 h collections and lower in creatinine (CR)-adjusted morning urine. Mean AR metabolite 24 h excretions correlated well with total WG (r(s) 0·31-0·52, P