BACKGROUND: There are some studies which have reported a higher diagnosis probability for PC if the DM occurred within the past 2-3 years. Information on the clinical profile of pancreatic cancer (PC) associated with diabetes mellitus (DM) is limited. The aim of the study was to compare clinic-morphological features in patients with new onset DM and PC and long lasting DM and PC, in order to detect new factors or markers which can help in early diagnosis of PC. METHODS: This study included 76 patients with pancreatic cancer admitted between 2000-2009 in the 4th Medical Clinic Cluj-Napoca; in group A 56 patients with PC and new onset of DM (< 24 months duration) were included and in group B 20 patients with PC and long standing diabetes (> 60 months duration) were included. We compared the demographic, clinical, biochemical and morphological characteristics of new onset or long lasting DM and pancreatic cancer. RESULTS: New onset DM was more prevalent (74% vs. 26%, p < .05) than long lasting DM among patients with PC. The patients with long lasting DM had a greater frequency of urban environment (100% vs. 55.6% p = .02), a higher body mass index (BMI)(32.1 SD 8.4 vs. 29.9 SD 6.7 kg/m2, p = .05), higher fasting blood glucose levels (182 mg/dL vs. 134 mg/dL, p = .008) and urinary ketone bodies (60% vs. 10.7%, p = .002) compared with those with new-onset DM and PC. There was no statistical difference regarding gender, median age, blood group, location and staging of tumours, long and hard alcohol and cigarettes consumption, between group A and B. CONCLUSIONS: New onset DM was more significantly frequent than long lasting DM in patients with PC. New onset diabetes DM associated with PC is frequent, mild and non-decompensated. In patients with PC and long lasting DM, the metabolic status and diabetes are imbalanced.