A man has been arrested in Alderney on suspicion of attempted murder, according to Guernsey police.
Officers were called to a "domestic incident" in the early hours of Wednesday.
A 55-year-old woman was found injured and, after treatment at Le Mignot Hospital, was transferred to Guernsey where she is in a "stable condition" .
Ch Insp Andrew Hockey said "additional police resources" had been deployed to assist the investigation.
With a population of about 2,000 people, Alderney falls under the jurisdiction of Guernsey Police.
Under normal circumstances, the Channel Island has just one sergeant and two constables stationed there.