A CMOS image sensor and a method for fabricating the same prevent a lifting effect of microlenses. Also, a diffused reflection of microlenses is prevented. The CMOS image sensor includes photodiodes, an interlayer insulating layer, metal lines formed in the interlayer insulating layer to electrically connect the respective photodiodes with each other, an oxide layer, a passivation layer to protect the CMOS image sensor from external sources, and microlenses formed to pass through the passivation layer at portions corresponding to the photodiodes.