Symptoms arising from primary bone sarcoma of the pelvic girdle are often insidious in onset and nonspecific in nature. To make the subtle initial signs and symptoms of these tumors more apparent to clinicians, we studied a cohort of patients who had a primary bone sarcoma of the pelvic girdle. Our purpose was to describe the initial clinical findings and to evaluate the duration, frequency, and implications of delays in the treatment of these tumors.We retrospectively analyzed the data on sixty-eight patients who had a primary bone sarcoma of the pelvic girdle. The data that we reviewed included demographic characteristics; histological diagnosis; anatomical location, size, and stage of the tumor; characteristics of the biopsy specimen; duration and description of symptoms before an accurate diagnosis was made; delay before recognition of the tumor on radiographs; results of diagnostic imaging; inaccurate diagnoses; type of intervention based on these inaccurate diagnoses; and outcome with regard to survival. There were forty high-grade sarcomas and twenty-eight low-grade sarcomas.Excluding two asymptomatic patients in whom the sarcoma was noted incidentally, the average duration of symptoms before an accurate diagnosis was made was ten months (median, six months; range, one month to four years). Common symptoms and findings on physical examination included pain in the buttock (twenty-three patients; 35 percent), a mass (twenty patients; 30 percent), sciatica (nineteen patients; 29 percent), pain in the hip (seventeen patients; 26 percent), pain in the groin (thirteen patients; 20 percent), and low-back pain (fourteen patients; 21 percent). In thirty (44 percent) of the sixty-eight patients, the pelvic sarcoma was not recognized initially and an inaccurate diagnosis was made. The misdiagnoses included a herniated lumbar disc, spinal stenosis, spondylolisthesis, tendinitis, bursitis, an inguinal hernia, a stress fracture, a pilonidal cyst, a recurrent urinary-tract infection, and degenerative arthritis of the spine, hip, and knee. Inappropriate treatment for these misdiagnoses included seven operative procedures (two laminectomies, two debridements, one hip arthrotomy, one total knee replacement, and one inguinal herniorrhaphy), six courses of nonsteroidal anti-inflammatory medications, five chiropractic adjustments, four trials of physical therapy, and three local injections of steroids. It took an average of seven months for the clinicians to arrive at the diagnosis of primary pelvic sarcoma. With the numbers available, no significant association between the duration of symptoms before an accurate diagnosis was made and the grade or the stage of the tumor could be detected. In addition, no association between the duration of symptoms and the survival of the patient (p = 0.54) could be determined, with univariate analysis. The grade and the stage of the tumor were strongly associated with the outcome, with a low tumor grade proving to be a favorable prognostic indicator for survival (p = 0.006).Patients who have a primary bone sarcoma of the pelvis often have had symptoms for a long duration that mimic those of more commonly encountered non-neoplastic musculoskeletal conditions. When a patient has symptoms that appear to be out of the ordinary, particularly refractory pain or pain at rest, physicians should include the pelvic girdle in the evaluation and should carefully examine a high-quality radiograph of the entire pelvis.