The first symptom of syphilis is a sore called a chancre (pronounced "shanker") that is usually painless. The sore begins at the site of infection as a small, solid, raised skin sore less than 1 cm (0.39 in.) across. It develops into a red, usually painless open sore with a scooped-out appearance. The sore usually does not bleed.

Two or more chancres may develop at the same time, usually in the genital area, but sometimes on the hands, mouth, or other body surfaces.

Chancres contain millions of syphilis bacteria and are highly contagious.