Prolactin has been proposed as a potent coactivator of platelet aggregation, possibly contributing to thromboembolic events. The objective of the study was to evaluate the relationship between prolactinoma and deep vein thrombosis (DVT), pulmonary embolism (PE), and cerebrovascular accident (CVA). Subjects were identified from a prospectively maintained pituitary database at the Cleveland Clinic. We retrospectively reviewed the charts of 544 subjects: 347 patients with prolactinomas (prolactinoma group) and 197 patients with nonfunctional pituitary adenomas (control group). Main outcome measures were DVT, PE and CVA. We found that 19 (5.5%) patients in the prolactinoma group and five (2.5%) patients in the control group had documented DVT, PE, or CVA, but this difference was not significant (p = 0.109). However, the mean initial prolactin level was higher at the time of diagnosis among prolactinoma patients than among controls (815.23 ng/ml vs. 15.90 ng/ml; p < 0.001). Among prolactinoma patients, 15 (5.5%) of 275 patients who underwent medical treatment (with cabergoline, bromocriptine, pergolide and/or other drug) and 4 (5.6%) of 72 patients who underwent transsphenoidal surgery had documented DVT, PE, or CVA, which suggests that dopaminergic therapy did not influence the risk of thromboembolic events. Hyperprolactinemia per se does not appear to predispose to a hypercoagulable state.