Two men have been arrested after a 36-year-old man turned up at Crawley hospital with a deep laceration to his neck last Thursday (February 4).
Police said officers were called after the victim was treated at the hospital on Thursday morning.
Two men, aged 35 and 39, have since been arrested in connection with the attempted murder.
The 39-year-old man was released on bail until March 3.
The 35-year-old man was released on bail until March 7, pending further enquiries.
Anyone who may have seen what happened is urged to get in touch with police.
Officers believe it took place between 10pm on Wednesday (February 3) and 9.45am on Thursday (February 4) in Ifield Road, Crawley.
Anyone with information is urged to report online or call 101 quoting Operation Bookworm.