Conceicao calls time on career
Conceicao, 35, joined PAOK in January last year in a surprise move and was made captain in his first full season for the Thessaloniki club.
Conceicao, capped 56 times by Portugal, has struggled with knee injuries this season. His club career featured spells at numerous clubs, including Porto, Inter Milan, Lazio, Parma and Standard Liege.
"This is one of the most difficult days of my career because it signals the end of my playing days," Conceicao told a news conference.
"I am satisfied though because I achieved many things and if I measure the good times against the bad, there were far more good moments."