OBJECTIVE The objective of the study was to study gall bladder volume in fasting and 45 minutes post-prandial, by real time ultrasound in healthy controls and diabetic patients with and without autonomic neuropathy and to compare them. METHODS Age, Sex and body mass index (BMI) matched 50 healthy subjects and 10 patients with insulin dependent diabetes mellitus and 40 patients with noninsulin dependent diabetes mellitus were evaluated according to National diabetes Data Group of National Institute of Health (1979) criteria: 1. Fasting (overnight) venous plasma glucose concentration of > 140 mg/dl on two separate occasions. 2. Following ingestion of 75 gms of glucose, venous plasma glucose concentration of > 200 mg/dl at second hour and at one other occasion during two hour test. Autonomic neuropathy was assessed by the presence of symptoms like dysphagia, abdominal fullness, nausea, vomiting, diarrhea +/- nocturnal, faecal incontinence or constipation, dysuria, urinary incontinence, the gustatory sweating, impotence etc. and were confirmed by standing test for orthostatic hypotension, hand grip test, Valsalva test and deep breaths test. RESULTS The study showed that: 1. Patients of diabetes mellitus had statistically significant larger fasting gall bladder volumes and these values were highly significant amongst patients with autonomic neuropathy. 2. Patients of diabetes mellitus and statistically significant larger post fatty meal gall bladder volume and these values were highly significant in patients with autonomic neuropathy. CONCLUSIONS We therefore conclude that impaired gall bladder contraction was found amongst patients of diabetes mellitus with autonomic neuropathy. The mechanism responsible for cholecystoparesis is attributed to vagal neuropathy. Incomplete gall bladder emptying leads to sequestration of cholesterol and nidus formation. Therefore gall bladder functions should be evaluated routinely in such patients and early intervention is recommended.