Renal ectopia is one of the most common renal abnormalities of kidney development. However, only a few cases of crossed fused renal ectopia have been reported in the literature. Although crossed renal ectopia is usually clinically silent, they is sometime responsible for infection and urinary stones and may be associated with a high incidence of ureteropelvic junction obstruction, vesicoureteral reflux and renal multicystic dysplasia. We report two new cases of crossed renal ectopia with fusion diagnosed in a context of kidney stones and urinary tract infection and review the mechanism and clinical features of this abnormality. We believe that Nephrologist must be familiar with this abnormality of kidney development, as a number of complications may appear during follow-up.