OBJECTIVE: Different subgroups can be identified in functional dyspepsia based on symptom type or severity, and may correlate with pathophysiological disturbances. In particular, female sex and severe fullness and vomiting have been reported to be strong independent predictors of slow solid gastric emptying. We aimed to determine if symptom patterns or severity could identify those with abnormal gastric emptying among patients with dysmotility-like functional dyspepsia and, for comparison, type I diabetes mellitus. METHODS: Patients with postprandial symptoms and documented functional dyspepsia by endoscopy (n = 551) and patients with type I diabetes who had postprandial dyspepsia (n = 247) enrolling in two separate randomized controlled trials were evaluated at baseline. Patients were assigned to either the delayed or normal gastric emptying strata, based on a validated C13 octanoic acid breath test with sampling over 4 h. A self-report questionnaire measured the presence and severity of eight symptoms on visual analog scales. The validated Nepean Dyspepsia Index measured the frequency, severity, and bothersomeness of 15 upper GI symptoms on Likert scales. RESULTS: Gastric emptying was definitely delayed (t1/2 > 192 min) in 24% of patients with functional dyspepsia and 28% with diabetes. Delayed gastric emptying was associated with female gender but not age or Helicobacter pylori status. The age- and sex-adjusted risk (odds ratio) of delayed gastric emptying for the upper GI symptoms ranged from 0.99 to 1.0 (all p values >0.2). The results were very similar in functional dyspepsia and diabetes. There was also no correlation between t1/2 and number of symptoms or symptom severity scores. CONCLUSIONS: Symptom prevalence and severity were similar in dyspeptic patients with and without delayed gastric emptying. Specific symptoms do not seem to be of predictive value in dysmotility-like dyspepsia for identifying alterations of gastric emptying.