The incidence and predisposing factors of urinary calculi are generally the same in both pregnant and non pregnant women, but anatomic changes during pregnancy make diagnosis and treatment a more challenging issue. We reviewed 16 patients (22 stones) of urinary stone during pregnancy between 1986 and 1996 at Kyung Hee Medical Center. The most common symptom was flank pain, seen in 81.3% of patients, while 68.8% of patients were displayed microscopic hematuria. In all cases, diagnosis was made by abdominal ultrasound, there was no need for other harmful investigate procedures. Forty point nine percent of the total stones (9/22) were passed spontaneously, double J stenting was carried out in three cases because of persistent pain or urinary tract infection (UTI), ureteroscopic stone removal was performed in one case. Based on our experience and a review of the literature, abdominal ultrasound should be performed first and in all cases appears sufficient for the diagnosis of a stone. In case of persistent pain or urinary tract infection, a double J stent is more effective than percutaneous nephrostomy.