Current primary hyperparathyroidism (PHPT) clinical presentation is asymptomatic in more than 90% of patients, while symptoms concern osteoporosis and rarely kidney stones. Here, we retrospectively investigated the prevalence of PHPT patients presenting with hypercalcemic-related symptoms (HS-PHPT) as cognitive impairment, changes in sensorium, proximal muscle weakness, nausea and vomiting, constipation, and severe dehydration, in a single center equipped with an emergency department and described their clinical features and outcome in comparison with a series of asymptomatic PHPT out-patients (A-PHPT). From 2006 to 2016, 112 PHPT patients were consecutively diagnosed: 16% (n = 18, 3M/15F) presented with hypercalcemic-related symptoms. Gastrointestinal symptoms occurred in 66% of HS-PHPT patients and cognitive impairment in 44%; one woman experienced hypertensive heart failure. Two-thirds of HS-PHPT patients were hospitalized due to the severity of symptoms. Comparing the clinical features of HS-PHPT patients with A-PHPT patients, no gender differences were detected in the two groups, while HS-PHPT patients were older at diagnosis (71 (61–81) vs. 64 (56–74) years, P=0.04; median (IQR)). HS-PHPT patients presented higher albumin-corrected calcium levels (12.3 (11.3–13.7) vs. 10.6 (10.3–11.3) mg/dl, P<0.001); 4 HS-PHPT presented corrected calcium levels >14 mg/dl. Serum PTH levels and total alkaline phosphatase activity were higher in HS-PHPT. Reduced kidney function (eGFR < 45 ml/min) was prevalent in HS-PHPT patients (42% vs. 5%, P=0.05). No differences in kidney stones and osteoporosis were detected, as well as in the rates of cardiovascular comorbidities and main cardiovascular risk factors. HS-PHPT patients had an age-adjusted Charlson Comorbidity Index higher than that of the A-PHPT patients and were on chronic therapy with a greater number of medications than A-PHPT patients. In conclusion, hypercalcemic-related symptoms occurred in 16% of PHPT patients. Risk factors were severity of the parathyroid tumor function, multimorbidity, and polypharmacy.