Introduction: Carcinoma pancreas has dismal prognosis and diabetes is a risk factor. Recent-onset diabetes in which pancreatic cancer was diagnosed were early-stage, suggesting possibility for early detection.^. Chronic pancreatitis (CP) is an inflammatory disease with progressive impairment of exocrine and endocrine functions; 19% alcoholic CP and 56% tropical CP were diabetic. Methodology: single centre retrospective comparative study is done in Department of Surgical Gastroenterology, in pancreatico-duodenectomy cases done from 01/01/2004 to 31/12/2013 for carcinoma in CP or denovo carcinoma pancreas. Results: Diabetes was associated more with CCP-Ca than denovo Ca (70.7%vs44.6%). Recent-onset diabetes was found more in CCP-Ca than Denovo Ca (41.1% vs 16.9%; p=0.003). Mean blood sugar in CCP-Ca was 193.3+110, significantly higher than Denovo-Ca 136.2+70. Uncontrolled diabetes at presentation was significantly more in CCP-Ca (43.1%) than Denovo-Ca (18.6%). Worse diabetes in CCP-Ca could be due to the baseline endocrine defects in CP. The mean blood sugar value in CCP-Ca was higher but not significant, in cholangitis compared to no cholangitis patients (202.03+104 vs 184.5+117.03; p<0.50). Mean blood sugar in Denovo-Ca was significantly higher in cholangitis compared to no cholangitis (148.8+78.2vs =115.7+45.7; p=0.002). Long duration diabetes in CCP might have sensitised tissues, may be the reason for lesser incidence of cholangitis in CCP-Ca. Conclusion: Though the parameters related to diabetes were worse among CCP-Ca than denovo-Ca, clinical complications and infective complications like cholangitis was not significant.