Acute infective sacro-iliitis is a rare condition. Though gonococcal arthritis is not uncommon, this organism does not appear to have been isolated from the sacro-iliac joint. The first proven case of gonococcal sacro-iliitis is reported here. Difficulties in correct diagnosis of infective sacro-iliitis are highlighted. Management of gonococcal sacro-iliitis is described. With the increase in number of gonococcal infections, a case can be made for routine culture of joint material N. Gonorrhoeae in cases of septic arthritis in patients at high risk.