Police said officers received a report of an assault in Jerrard Road, Tangmere at about 4.22pm on Saturday.
A police spokesman said: “A 21-year-old local man sustained facial injuries and was taken to hospital for treatment.
“Following enquiries, an 18-year-old man from Chichester was arrested on suspicion of committing grievous bodily harm.
“He has been released on bail until September 1 pending further enquiries.”
Anyone who saw what happened is asked to report it online or call 101, quoting serial 1102 of 04/08.
Alternatively, you can visit the Crimestoppers www.crimestoppers-uk.org website or contact the independent charity anonymously on 0800 555 111.