Bicipital peritendinous effusion (BPE), a common ultrasonographic finding of the long head of the biceps tendon, may be associated with shoulder joint derangement, but supporting evidence from large-scale studies is lacking. The aim of this cross-sectional study was to determine the strength of the association between BPE and sonographic abnormalities of the shoulder joint. We reviewed the sonographic reports of patients with suspected shoulder disorders investigated ultrasonographically between January 2011 and January 2012. BPE was graded according to its measured thickness as absent (<1 mm), mild (1-2 mm), moderate (2-3 mm) or severe (>3 mm). The associations between BPE and sonographic abnormalities were examined using multinomial logistic regression adjusted for age, gender, affected side and clinical diagnosis of frozen shoulder. The prevalence rates of absent, mild, moderate and severe BPE among the 907 shoulders examined were 64.1%, 17.8%, 10.4% and 7.7%, respectively. Frozen shoulder was associated with mild BPE (relative risk [RR] vs. participants without BPE = 1.83, 95% confidence interval [CI] = 1.28-2.50). Sonographic findings of biceps tendinopathy, subdeltoid bursitis and full-thickness tears of the supraspinatus tendon were significantly associated with the entire spectrum of BPE, whereas subscapularis tendon tears were significantly associated with moderate (RR = 2.47, 95% CI = 1.29-4.69) and severe (RR = 3.11, 95% CI = 1.51-6.33) BPE. Severe BPE was associated with articular-sided partial-thickness tears of the supraspinatus tendon (RR = 14.32, 95% CI = 4.30-34.35), posterior recess effusion (RR, 7.98, 95% CI = 1.44-34.93) and biceps medial subluxation (RR = 7.25, 95% CI = 1.90-22.33). Our study indicates that BPE is related to various shoulder abnormalities and that the strengths of these associations depend on the severity of BPE. Clinicians encountering BPE should grade its severity and be alert for hidden lesions of the shoulder joint.