This study was performed to clarify the cause of shoulder pain using sonography and to evaluate the relationship between the sonographic findings and the motor recovery stages in stroke patients with hemiplegic shoulder pain. Between March 2005 and January 2007, 71 consecutive stroke patients with hemiplegic shoulder pain underwent shoulder sonography. For comparison, bilateral shoulder joints were evaluated in 20 of the 71 patients. The interpretations of the sonographic findings were based on the findings of previously published studies. Whether a correlation existed between the sonographic findings and the motor recovery stages was determined. Subacromial-subdeltoid (SA-SD) bursal effusion (n = 36) was the most common abnormality seen on sonography. Tendinosis of the supraspinatus tendon (n = 7), partial-thickness tear of the supraspinatus tendon (n = 6), and full-thickness tear of the supraspinatus tendon (n = 2) were also noted. Biceps tendon sheath effusion (n = 39) and normal findings without any biceps tendon sheath effusion (n = 13) were detected. Clinicians managed each patient's shoulder pain on the basis of the sonographic findings. No statistically significant correlation was found between the grade of sonographic findings and Brunnstrom stage (p = 0.183). A shoulder with hemiplegia had a higher number of abnormal sonographic findings than a noninvolved shoulder (p = 0.007). The cause of shoulder pain was variable and there was no correlation between the stages of motor recovery and the grades of sonographic findings in patients with hemiplegic shoulder pain.