The adult patient who complains of anterior hip pain is a dilemma frequently encountered by the primary care physician. Detailed history taking, physical examination, and plain x-ray films are indicated for the initial evaluation. Anterior hip pain is often diagnosed as musculoskeletal strain/sprain and treated with a conservative regimen represented by the acronym NICER (nonsteroidal anti-inflammatory drugs, ice, compression, elevation, and rest) with or without physical therapy. On occasion, this therapy fails to eradicate the symptoms. When these symptoms are refractory to diagnosis by conventional means, a more comprehensive evaluation of the etiology is warranted. Refractory pain is defined in the authors' practice as pain that persists after 4 weeks of initial conservative management. This subsequent evaluation includes the use of such laboratory tests as complete blood cell count with differential count, Chem 20 health profile, erythrocyte sedimentation rate, and an arthritic panel (assessment of rheumatoid factor, antinuclear antibody, C-reactive protein). Ancillary radiologic tests warranted include a nuclear bone scan, a magnetic resonance imaging scan, a computed tomography arthrogram with hip aspiration, and/or a scan of white blood cells labeled with indium 111. The test chosen depends on the etiology most suspected. A useful diagnostic algorithm for the investigation of anterior hip pain in the adult is provided. An illustrative case presentation of carcinoma of an unknown primary site presenting as anterior hip pain demonstrates the algorithm as it applies in the authors' practice.