Although pancreatic neuroendocrine neoplasms (PNENs) are relatively rare tumors, their number is increasing with advances in diagnostic imaging modalities. Even small lesions that are difficult to detect using computed tomography or magnetic resonance imaging can be detected with endoscopic ultrasound (EUS). Contrast-enhanced EUS is useful, and not only diagnosis but also malignancy detection have become possible by evaluating the vascularity of tumors. Pathological diagnosis using EUS with fine-needle aspiration (EUS-FNA) is useful when diagnostic imaging is difficult. EUS-FNA can also evaluate the grade of malignancy. Pooling the data of the studies which compared the PNENs grading between EUS-FNA samples and surgical specimen, the concordance rate was 77.5% (κ-statistic: 0.65, 95% confidence interval = 0.59 - 0.71, P< 0.01). EUS is a particularly important modality for the treatment of PNENs.