Children with chronic renal failure (CRF) show a reduced appetite for sweet foods. Sensory responses to sweet stimuli were investigated in 45 children with CRF, 39 dialyzed patients (HD) and 25 controls(C). Two familiar foods were prepared in 5 sucrose concentrations: 1, 5, 10, 15, 20% for soft white cheese (SWC): 10, 20, 30, 40, 60% for apple sauce (AS). When identifying the sweeter of two SWC samples, CRF(15%) and HD (18%) made more mistakes than C (5%). When testing AS, mistakes were comparable between groups (25, 21, 19%). Preferences differed according to diagnosis group. The sweetest SWC was preferred by 40% of CRF and C and by only 22% HD; the least sweet SWC was preferred by 5% of C, 10% of CRF and 16% of HD. In AS, the highest concentrations were preferred by CRF and C, median concentration by HD. Plasma zinc had no clear effect on taste. Altered preferences for sweet foods in patients suggest post-ingestive adverse effects of sucrose resulting from an altered sucrose metabolism.