Introduction: Sphincter of oddi dysfunction (SOD) may have a role in chronic acalculous cholecystitis (CAC). The purpose of this study is to 1) evaluate incidence of SOD in patients with CAC 2) to correlate SO pressures with patient outcome and 3) to correlate intra-operative manometry with postoperative ERCP/manometry. Method: Transcystic biliary manometry was attempted in one hundred and twenty nine patients with CAC during laparoscopic cholecystectomy between Aug/94 and Sept/02. Diagnosis of SOD was made if the average basal pressure was greater than 40 mm Hg. The biliary manometry data was correlated to the patients' outcome using Fisher's exact and Student's t-test. Patients with persistent or recurrent symptoms underwent postoperative ERCP/manometry/sphincterotomy. This data was then correlated with operative manometry and their outcomes followed. Results: Intraoperative manometry was completed in 91 patients but seven were lost to follow-up. Follow-up was a mean of 32 months (0.25-99mo). Fifty-five (65%) had SOD. Forty-three (78%) of these had resolution or significant improvement and twelve (22%) had persistence of symptoms. Twenty-nine (35%) patients had normal SO function. Twenty-four (83%) had resolution or significant improvement and five (17%) had persistence of symptoms. Outcomes were similar (p=0.62) regardless of the SO pressure. Pain score (0-10) was obtainable from 49% of patients with resolution/improvement, and went from 8.5 to 1.1 (p<0.0001). Five (12%) patients with SOD recurred after the initial operation. Mean time to recurrence was 23mo (11-40mo). All improved after endoscopic sphincterotomy. Patients with persistent symptoms also had a trend towards improvement with postoperative endoscopic sphincterotomy. Patients who had postoperative ERCP/manometry, intraoperative findings were confirmed. Conclusion: SOD is a significant factor in CAC. Most with CAC improve after cholecystectomy regardless of the SO pressures. There is a good concordance between intra-operative and post-operative manometry. Preliminary data suggests a correlation between SO pressures and resolution/improvement following endoscopic sphincterotomy