A 41-year-old man is in hospital after being stabbed during a row on Saturday morning on the Garth Estate, in Abertridwr.
A 23-year-old man was arrested in connection with the incident, which took place at about 11am, on suspicion of assault
Gwent Police said they were called following a disturbance at an address on the Garth Estate between the two men.
A spokeswoman said an area near the Windsor Hotel, in Caerphilly Road, Senghenydd was cordoned off later that evening as part of the investigation.
The 41-year-old man was taken to Caerphilly Miners’ Hospital for treatment of a stab wound and was later transferred to the Royal Gwent Hospital in Newport.
Police have said he is in a stable condition.
The 23-year-old man was treated for superficial cuts and was later released without charge following advice to Gwent Police from the Crown Prosecution Service.