Objectives: The aim of this study was to determine and compare the prevalence of malnutri-tion in pancreatic and colorectal cancer patients attending the outpatient clinic presenting for diagnosis, therapy or follow-up. Additionally, the study investigated the benefit of nutritional intervention, which includes oral nutritional supplements (ONS) and parenteral nutrition (PN) in the pancreatic cancer (PC) group and the colorectal cancer (CRC) group. Subjects and methods: 108 patients accounted for the whole study group comprising CRC (N = 57) and PC (N = 51) patients. All patients were pre-screened and if this was positive the main screening followed. This was performed by the dietitian with the NRS. Patients with a score <3 were rescreened 8 weeks later and patients with NRS ≥3 were assessed by the dieti-tian and the oncologists for malnutrition (BMI, weight loss, reduced skeletal muscle mass). 43% of the whole study group received an intervention (ONS or PN). 71% received ONS and/or PN in the PC group compared to just 17% in the CRC. At the end of the study patients’ weight, complaints and appetite were compared to first screening. These three variables were used to evaluate the benefit of the intervention. Results: From the overall 108 patients 71% were malnourished. In the PC group 67% were malnourished compared to 59% in the CRC group. There was no significant difference be-tween the two groups (P=0.593). However, in regard of low BMI, which was one variable defining malnutrition, 22% of PC patients presented with a low BMI in comparison to 7% of CRC patients (P=0.029). Comparing the weight loss (>5%), also one criterion of the defini-tion, there was a significant difference (P<0.001). 71% patients with PC and 17% of patients with CRC received an intervention (P<0.001). When looking at the outcome of benefit 43% of PC patients experienced a benefit after intervention compared to 14% in the CRC patients. Benefit was seen in both groups but there was no significant difference between them (P=0.162). Conclusions: As expected prevalence of malnutrition is higher in patients with pancreatic cancer compared to patients with colorectal cancer. Both groups benefit from intervention. Due to the high prevalence of malnutrition in the studied groups, all healthcare workers should be aware of the consequences caused by malnutrition as well as the importance of ear-ly interventions. Nutritional evaluation should be part of every cancer patient’s treatment.