It is estimated that cholelithiasis occurs in 20. million people in the United States, and 500,000 people will undergo cholecystectomy annually. Furthermore, 5% of those who undergo surgery will have acalculous cholecystitis, an uncommon disease that can result in gallbladder perforation or death. Diagnosis of acalculous cholecystitis is frequently delayed due to a confusing clinical presentation and nonspecific diagnostic findings. The following case report describes the presentation of a 19-year-old female with a 12-month history of right upper quadrant pain, and the serologic and radiographic tests that led to a diagnosis of acalculous cholecystitis. Primary care providers should consider this disease a possibility in any patient who presents with right upper quadrant pain.