Background/Aims: A high-quality sample allows for next-generation sequencing and the administration of more tailored precision medicine treatments. We aimed to evaluate whether heparinized wet suction can obtain higher quality samples than the standard dry-suction method during endoscopic ultrasound (EUS)-guided biopsy of pancreatic masses. Methods: A prospective randomized crossover study was conducted. Patients with a solid pancreatic mass were randomly allocated to receive either heparinized wet suction first or dry suction first. For each method, two needle passes were made, followed by a switch to the other method for a total of four needle punctures. The primary outcome was the aggregated white tissue length. Histological blood contamination, diagnostic performance and adverse events were analyzed as secondary outcomes. In addition, the correlation between white tissue length and the extracted DNA amount was analyzed. Results: A total of 50 patients were enrolled, and 200 specimens were acquired (100 with heparinized wet suction and 100 with dry suction), with one minor bleeding event. The heparinized wet suction approach yielded specimens with longer aggregated white tissue length (11.07 mm vs 7.96 mm, p=0.001) and less blood contamination (p=0.008). A trend towards decreasing tissue quality was observed for the 2nd pass of the dry-suction method, leading to decreased diagnostic sensitivity and accuracy, although the accumulated diagnostic performance was comparable between the two suction methods. The amount of extracted DNA correlated positively to the white tissue length (p=0.001, Spearman ̕s ρ=0.568). Conclusions Heparinized wet suction for EUS tissue acquisition of solid pancreatic masses can yield longer, bloodless, DNA-rich tissue without increasing the incidence of adverse events (ClinicalTrials.gov. identifier NCT04707560).