The old urinary calculi of the votive offerings in the pilgrimage church at Grafrath offer the possibility of analysing the components by infrared spectroscopy to give insights into factors that might influence their formation. A total of 166 specimens were taken from 139 objects (134 stones, 5 bones), in some stones from different layers. Spectral analysis showed typical components for urinary calculi in 127 stones. These were compared with a control group of 98 urinary stones from carriers (77 male, 21 female) during 2007/2008 in Bavaria. The percentage of occurrence of ammonium acid urate (NH(4)U) was high in the old stones (68.0%) versus the 2007/2008 group (1.0%). In uric acid (HS) there was no relevant difference between the two groups, whereas the occurrence of the oxalates whewellite (Whe) and weddellite (Wed) was much less in the old stones (Whe 18.1-69.4%, Wed 7.9-26.5 %). The phosphates differ in the components in favour of brushite in the old stones. The high occurrence of NH(4) in the old stones is comparable with (a) the old pre-1900 collection of Norwich (England), especially with the pre-1800 juvenile bladder stones, and (b) urinary stones in endemic areas of stone disease in children such as in North Thailand. Data about the Grafrath stone carriers (name, age, hometown) are not available but can indirectly be derived from the miracle books (1444-1728) of Grafrath with 12,131 reports; 1,165 had urologic disease of which 70% were children with urinary calculi coming from areas of Upper Bavaria and Swabia. The finding of a high NH(4)U content indicates that this area might have been a stone belt for bladder stones in children. Under- or malnutrition with low protein and low fluid intake may be the aetiologic factor.