Objective: Gastroparesis is a well-known complication of diabetes mellitus, both in symptomatic and asymptomatic patients. Esophageal dysmotility has also been described, but is not as well-characterized. The etiology and effect of these complications need to be clarified. The aim of the present study was to evaluate esophageal and gastric motility, complications, gastrointestinal symptoms, and plasma biomarkers in a cross-sectional study comprising patients with diabetes mellitus. Methods: Patients with diabetes were consecutively asked to participate, and eventually 84 volunteers were included in the study. Esophageal manometry and the gastric emptying test were performed in all patients. Type of diabetes, symptoms, diabetic complications, body mass index (BMI), and biomarkers were recorded. Patients were interviewed about gastrointestinal symptoms. Results: Esophageal dysmotility was present in 63% of patients and gastroparesis in 13% of patients. There was no difference in dysmotility between patients with type 1 and type 2 diabetes or between genders. Gastrointestinal symptoms did not correlate to objective findings. Age correlated negatively with gastric emptying rate (p = 0.004). Patients with esophageal dysmotility had longer duration of diabetes compared to those without dysmotility (p = 0.043). In logistic regression analysis, retinopathy was strongly associated with esophageal dysmotility, independent of duration (p = 0.003). Conclusion: Esophageal dysmotility is more common than gastroparesis in diabetes mellitus independent of gender, symptoms, and type of diabetes. There is a strong association between retinopathy and esophageal dysmotility.