Two hundred renal calculi were analysed by pellet technique. Chemical composition of the outer shell and core of urinary calculi was determined separately wherever possible, otherwise the whole stone was powdered and analysed. The most frequently occurring components in both pure and mixed stones were calcium oxalate (whewellite/weddellite) (73.5%), uric acid (anhydrous/hydrated) (31%), apatite/whitlockite (20%), struvite (18%) and ammonium acid urate (7.5%). Calcium oxalate (37%), mixture of calcium oxalate and apatite/whitlockite (19%), and uric acid (19.4%) served as nuclei of urinary stones. Whitlockite did not occur in its pure state but its presence was detected in mixed form with calcium oxalate, struvite and apatite. Statistical combinations in relation to chemical composition of urinary calculi were computed and compared with the results of other workers. Calcium oxalate was the commonest component of pure as well as mixed stones. Only one stone was composed of cystine. Stones from children and factors such as sex, age, and environment have been discussed.