Recently, increased and disorganized expression of CD44 variant exons (CD44v) has been demonstrated in several types of human malignancy. We tried to investigate CD44v expression in pancreatic juice from patients who underwent endoscopic retrograde pancreatography. We analyzed 24 patients with pancreatic neoplasms diagnosed histologically (adenocarcinoma, 17; adenoma, 7) and 15 patients with non-neoplastic lesions. The expression of CD44v mRNA in pancreatic juice was detected by using the reverse-transcription polymerase chain reaction technique followed by Southern hybridization with exon-specific probes. Of 17 patients with adenocarcinoma, 14 (82%) showed expression of CD44v6 mRNA and 11 (65%) showed expression of CD44v2 mRNA. Of 7 patients with adenoma, 6 (86%) were positive CD44v6 mRNA expression and 2 (29%) for CD44v2 mRNA expression; while, out of 15 patients with non-neoplastic lesion, 5 (33%) showed positive findings for CD44V6 mRNA and 3 (20%) for CD44v2 mRNA. Comparing of diagnostic accuracy among CD44v6, CD44v2 and cytological examination, the sensitivities for adenocarcinoma were 82%, 65% and 41% respectively. However, the specificity was lower in CD44v6 (50%), CD44v2 (77%) than in cytology (100%), because CD44v was positive in adenoma cases and normal cases. A combination of RT-PCR analysis for the expression of CD44v with cytological examination in the pancreatic juice may increase the accuracy of diagnosis for pancreatic cancer.