There are limited data regarding the frequency of hypertension in nonfunctioning adrenal incidentaloma (NFAI). Our objectives were to investigate rates of hypertension and resistant hypertension in NFAI patients, and compare them to a control group without adrenal adenoma. We also aimed to evaluate the relationship between cortisol levels after 1 mg-dexamethasone suppression test (DST) and hypertension in NFAI patients. We selected 40 patients with NFAI and 40 control patients over the age of 18 without adrenal lesions on abdominal imaging. Data regarding hypertension, resistant hypertension, number, and type of antihypertensive drugs were collected from each subject. Blood samples for C-reactive protein (CRP), plasma adrenocorticotropic hormone (ACTH) and dehydroepiandrosterone sulfate (DHEA-S) were also collected from the patients. Age, gender, race, smoking status, menopause status and BMI were comparable between patient and control groups. Patients with NFAI had a higher frequency of hypertension (72.5 vs. 47.5%; p = 0.04), resistant hypertension (37.9 vs. 11.1%; p = 0.04) and took three or more antihypertensive drugs (33.3 vs. 5.2%; p = 0.002) when compared to the controls, respectively. NFAI patients with hypertension had higher mean cortisol levels after 1 mg-DST when compared to NFAI patients without hypertension (1.3 ± 0.3 vs. 1.0 ± 0.4; p = 0.03, respectively). We found a negative correlation between cortisol levels after 1 mg-DST DHEA-S levels (r = -0.61; p < 0.001) and a positive correlation with CRP levels (r = 0.44; p = 0.02). In conclusion, NFAI patients presented a higher frequency of hypertension, resistant hypertension and used more antihypertensive medications when compared to the control group. We found an association between hypertension in NFAI patients and cortisol levels after 1 mg-DST.