A general observation of clinicians suggests that the prevalence ofurolithiasis is fairly high in Kathmandu but so far no systematic study has been undertaken here to explore the etiopathogenesis of disease in this region. In this preliminary communication, we present herewith the qualitative composition of 47 renal stones collected from surgical patients admitted to NMCTH over a period of 13 months (July 2005 to July 2006). All stones were of mixed type. Calcium was present in all stones. Oxalate, phosphate and uric acid were present in 95.7%, 87.2% and 34.0% patients respectively. The probable composition, as construed from analysis, suggests that calcium oxalate stones are predominant. Strikingly, the prevalence was very high in e"20 yrs age group.