We assessed the trends, characteristics, and consequences of potentially avoidable hospitalizations (PAH) for hypertension in Switzerland, for the period 1998 to 2018. Data from 117,507 hospitalizations (62.1% women), minimum age 20 years. Hospitalizations with hypertension as the main cause for admission were eligible. PAH for hypertension was defined according to the Organization for Economic Cooperation and Development criteria. The age-standardized rates of PAH for hypertension increased from 43 in 1998 to 81 per 100,000 in 2004, to decrease to 57 per 100,000 inhabitants in 2018. Compared to non-PAH, patients with PAH for hypertension were younger, more frequently women (66.9% vs. 56.7%), non-Swiss nationals (15.9% vs. 10.9%), were more frequently admitted as an emergency (78.9% vs. 59.5%), and by the patient's initiative (33.1% vs. 14.1%). Patients with PAH had also fewer comorbidities, as per the Charlson's index. Patients with PAH for hypertension were more frequently hospitalized in a semi-private or private setting, stayed less frequently in the intensive care unit (4.6% vs. 7.3%), were discharged more frequently home (91.4% vs. 73.0%), and had a shorter length of stay than patients with non-PAH for hypertension: median and [interquartile range] 5 [3-8] vs. 9 [4-15] days. In 2018, the total costs of PAH were estimated at 16.5 million CHF, corresponding to a median cost of 4936 [4445-4961] Swiss Francs per stay. We conclude that in Switzerland, PAH have increased, represent a considerable fraction of hospitalizations for hypertension, and carry a non-negligible health cost.