Bisphophonates (BPs) are a group of drugs used in treating bone diseases, which may lead to the deve lopment of the osteonecrosis of the jaw (ONJ). The negative impact of BPs on angiogenesis is among the causes of ONJ. The specific mechanisms of complications are unknown. What is taken into consideration is the trauma background, which, in combination with the implemented BP treatment, can induce bone ne crosis. One of the possible consequences of necrotic change progression is the development of an oronasal fistula. Treatment generally requires a surgical intervention. The paper describes the course of treatment of an oronasal fistula in a patient with BP osteitis, currently using an upper denture. The fistula arose a year after the removal of a protruding sequestrum in the region of the hard palate. An attempt was made to treat the fistula by the mobilization of soft tissues from the pa late and the bilayered closure of the fistula with the use of a pedicled connective tissue graft on the greater palatine artery, along with a Tinti-ParmaBenfenati (TPB) flap. The patient was subjected to appropriate postprocedural measures. Regular followups did not reveal any abnormalities in the course of healing. The use of the abovementioned procedure proved to be an effective method of treatment of an oronasal fistula. The use of a pedicled connective tissue graft for the closure of the oronasal fistula caused by BP therapy had a significant effect on the treatment outcome.