Background and Aims: To date, surveillance of high-risk individuals for pancreatic ductal adenocarcinoma (PDAC) has not lived up to expectations, as identification of curable stages through imaging remains challenging. Biomarkers are therefore needed. Pancreatic juice (PJ) may be a promising source, because it is in direct contact with the ductal epithelial lining from which PDAC arises. We aimed to develop a panel of biomarkers from serum and PJ to detect PDAC for future surveillance purposes. Methods: All patients who underwent PJ collection on secretin stimulation at the Erasmus MC were included. Both PJ and serum were evaluated. Protein levels were determined by the Lowry assay. Potential biomarkers (interleukin-8, interferon-γ, neutrophil gelatinase-associated lipocalin [NGAL], mucin 5, subtype AC [MUC5AC], mucin 2, phospholipase A2 group IB) were selected based on previously reported outcomes and assessed with enzyme-linked immunosorbent assay. Serum carbohydrate antigen 19-9 (CA19-9) values were determined by electrochemiluminescence immunoassay. Results: This study included 59 cases and 126 surveilled control subjects (who underwent PJ collection), of whom 71 had a hereditary predisposition (35 genetic, 36 familial) and 55 had (suspected neoplastic) pancreatic cysts. CA19-9 values were available for 53 cases and 48 control subjects. Serum CA19-9, as well as PJ interleukin-8, NGAL and MUC5AC, were associated with PDAC independent of age, gender, and presence of diabetes mellitus. Serum CA19-9 had a significantly higher area under the curve (AUC; .86; 95% confidence interval [CI], .79-.94) than individual PJ markers (AUC, .62-.70). A combination of PJ markers and serum CA19-9 (panel 2: sensitivity 42% [95% CI, 29-57] and specificity 96% [95% CI, 86-100]) did not improve diagnostic performance compared with CA19-9 alone (sensitivity 70% [95% CI, 56-82] and specificity 85% [95% CI, 72-94]). Conclusions: High levels of serum CA19-9 and PJ-derived proteins are associated with PDAC. Prospective surveillance studies including individuals at risk of developing PDAC are required to validate these findings.