According to local media reports the suspect is the dead couple's son.
Police found a baseball bat in the house in Perchtoldsdorf, which is believed to be the murder weapon.
Police spokesman Johann Baumschlager said that the married couple – reported to be 75 and 85 years old – died after being violently beaten. He confirmed that a suspect, the son of the couple, had been arrested and that it was he who had called the emergency services to say that his parents were dead, and that he had killed them. When the police arrived he came out of the house and made no attempt to resist arrest.
Baumschlager told the Krone newspaper that the suspect had cared for his bedridden parents for some time, and had no previous criminal convictions.
The 48-year-old is currently being questioned by police, as are his two sisters.