DYFED-Powys Police is investigating an incident that happened at The Met Bar, Llanelli, on Saturday (Mar 16).
Ambulance were called to the scene and alerted police of the incident at 10.55pm.
The man suffered a head injury and was unconscious outside the public house.
He was conveyed to hospital by paramedics. He is in a stable condition.
Officers are working to establish the sequence of events that led to the man falling.
Anyone with information that can help officers with their investigation is asked to report it by calling 101.
If you are deaf, hard of hearing or speech impaired text the non-emergency number on 07811 311 908. Quote reference: DPP/3011/16/03/2019/02/C