ICU patients have more than doubled in the last month, according to data from the Ministry of Health.
On August 28, 751 patients were admitted to the ICU hospital unit. But, by September 29, the report showed 1,535 patients.
The majority of ICU admissions were made in Madrid, with 484 patients in the capital.
This figure is more than triple the number in Andalusia, which is in second position with 173 ICU patients.
Spain is the second country in Europe to have returned to the same infection rate as at the start of the pandemic.
Russia leads the number of coronavirus cases (1,159,573) followed by Spain (758,172), France 542,639 and the UK 439,013.
However, the UK has had the highest number of total deaths with more than 42,000.