Vitamin D-dependent rickets(VDDR) is a rare autosomal disorder, characterized by hypocalcemia, hypophosphatemia, increased alkaline phosphatase, secondary hyperparathyroidism and many other clinical features. Type I VDDR is due to congenital defects of renal 1${alpha}$-hydroxylase, the enzyme responsible for the conversion of 25-(OH)D3 to 1,25-$(OH)_2D3$. Type II VDDR arise from target organ resistance to 1,25-$(OH)_2D3$. Unilateral renal aplasia is generally thought to result from a lack of induction of the metanephric blastema from the ureteral bud, which may be secondary to ureteral bud maldevelopment and/or to a problem with the formation of the mesonephric duct. The incidence of unilateral renal aplasia is approximately 1/500-3,200. Type 1 VDDR associated with unilateral renal aplasia has not been reported yet. Thus we report a case of a 3 month old female infant diagnosed as type 1 VDDR with unilateral aplasia of kidney.