Provided is a method of fabricating a memory device. The method includes defining a cell region and a driving region on a substrate, forming driving transistors on the driving region, forming a first bit line in the cell region, a first unit memory cell disposed on an upper surface of the first bit line, a word line disposed on upper surfaces of the first unit memory cells, and a second unit memory cell disposed on an upper surface of the word line, forming a planarization layer configured to fill between the second unit memory cells, and including second bit line grooves on the upper surfaces of the first bit lines, bit line contact vias in the second bit line grooves, floating electrode grooves on upper surfaces of ends of the word lines, and a first floating contact via and a second floating contact via in each of the floating electrode grooves, simultaneously forming second bit lines in the second bit line grooves, bit line contact electrodes in the bit line contact vias, floating electrodes in the floating electrode grooves, first floating contact electrodes in the first floating contact vias, and second floating contact electrodes in the second floating contact vias.