At 3.08pm today South Wales Police received a 999 call reporting a stabbing in Tin Street, Roath.
A man has been taken to the University Hospital of Wales, Cardiff, with a stab wound to his chest area.
His injuries are not thought to be life-threatening and he is a stable condition.
Officers are actively looking for two men who are believed to be involved in the assault and known to the victim.
A police cordon is in place to allow for forensic examination, CCTV is being checked to identify those responsible, detectives are conducting house to house enquiries and extra patrols will continue this evening.
Armed police attended the location as a precaution to ensure the safety of the public and officers.
Anyone with information is asked to contact South Wales Police on 101 or Crimestoppers anonymously on 0800 555 111 quoting occurrence number 62140021228.