Urolithiasis complicates up to one in every 200 pregnancies; consequently, the practicing obstetrician should be aware of the symptoms of urolithiasis, the diagnostic procedures available for its diagnosis, and their associated risks. These include ultrasound, urography, and magnetic resonance imaging. Diagnosis of urolithiasis during pregnancy can be a challenge as a result of the normal physiological changes of pregnancy. Conservative management is the first-line treatment for noncomplicated urolithiasis in pregnancy. If spontaneous passage of the stone does not occur or if complications develop, urologic consultation should be obtained. Several obstetric complications have been associated with urolithiasis, including preterm labor and preterm premature rupture of membranes, although the reported rates of these complications in association with urolithiasis vary widely and overlap normal background rates. Given that urolithiasis will be encountered by most obstetricians, and that obstetricians are often on the front line of management for this condition, an appreciation of current diagnostic modalities, treatment protocols, and associated potential obstetric complications is warranted. BACKGROUND Obstetricians & Gynecologists, Family Physicians. OBJECTIVE After completion of this article, the reader should be able to recall that urolithiasis is common in pregnancy, state that there are a variety of diagnostic procedures, summarize that conservative treatment is usually successful, and explain that complications of pregnancy usually occur when there is failure of conservative treatment.