Bijlow kept five clean sheets in 16 appearances after joining mid-season — a return that demonstrated immediately why the club pursued him.
Club chief of football Diego Lopez said: "We are pleased to provide continuity and stability in defence, in a fundamental role like goalkeeper.
"Justin has proven to be a modern goalkeeper suited to our game. He has transmitted security and reliability in the defensive phase.
"We go forward together convinced that next season can bring further satisfaction."
Bijlow, formerly of Feyenoord, expressed equal enthusiasm about his new environment.
"I am happy to be able to continue wearing this shirt. I immediately felt at home here in Genoa — I found warm supporters capable of carrying you and giving you a great charge. Settling in here was easier than I thought, also thanks to my team-mates, the coaching staff and an organised and ambitious club.
"I cannot wait to get back on the pitch to defend the red and blue colours and I am ready as always to give my best."