Clinical use of extracorporeal shockwave lithotripsy (ESWL) in the noninvasive management of urinary calculi is highly effective and practical. But its results vary in relation to several factors including localization, size and the chemical composition of the stones. Moreover, the anatomy of the kidneys treated is another contributing factor to the success rate of ESWL in upper urinary tract stones. Currently, except cystine and struvite stones, the efficiency of ESWL has been proved and has become the most outstanding therapy for calculi in a great number of stone centers. In this study, the efficiency of ESWL treatment in respect to the concentrations of 4 different trace elements (Cu, Fe, Mg and Zn) in the chemical composition of Ca-oxalate monohydrate stones have been evaluated in 20 patients.