Biliary pseudolithiasis has been reported in patients who received ceftriaxone therapy. In addition to biliary sludge formation occasional reports of ceftriaxone-induced nephrolithiasis have been published. In general, these adverse effects will develop after seven to ten days of treatment. We report on a seven-year-old boy with ceftriaxone-associated biliary pseudolithiasis and nephrolithiasis four days after initiation of treatment. Patients receiving a high dose of ceftriaxone and developing colicky abdominal pain should be considered for ultrasound and a change in antibiotic therapy if appropriate.