A package structure including an organic interposer substrate, a semiconductor die, conductive bumps, an underfill, and an insulating encapsulation is provided. The organic interposer substrate includes stacked organic dielectric layers and conductive wirings embedded in the stacked organic dielectric layers. The semiconductor die is disposed over and electrically connected to the conductive wirings of the organic interposer substrate, and the semiconductor die includes chamfered edges. The conductive bumps are disposed between the semiconductor die and the organic interposer substrate, and the semiconductor die is electrically connected to the organic interposer substrate through the conductive bumps. The underfill is disposed between the semiconductor die and the organic interposer substrate, wherein the underfill encapsulates the conductive bumps and is in contact with the chamfered edges of the at least one semiconductor die. The insulating encapsulation covers the organic interposer substrate and laterally encapsulates the least one semiconductor die and the underfill.