The L-shaped or tandem kidney is a type of crossed ectopia with fusion in which the crossed kidney assumes a transverse position during its attachment to the inferior pole of the other kidney. Calculus formation is a well-known sequel of congenital abnormalities of the urinary tract and we like to present two patients harbouring calculi in L-shaped kidneys treated by extracorporeal shock wave lithotripsy (ESWL). The first patient had a calculus in renal pelvis of the transverse kidney. The second case had multiple calculi in renal pelvis and calices of the vertically positioned kidney. After three sessions, first patient was stone free, whereas no fragmentation in the second case. As a conclusion, ESWL might be an option for L-shaped kidneys. © Springer 2005.