Highly efficient and fully solution-processed white organic light-emitting diodes (WOLEDs) based on fluorescent small molecules and a polar conjugated polymer as electron-injection material are reported. The emitting layer in the WOLEDs is a blend of new blue-, green-, and red-fluorescent small molecules, with a blending ratio of 100:0.4:0.8 (B/G/R) by weight, and a methanol/water soluble conjugated polymerpoly[(9,9-bis(30-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) acts as the electron-injection layer (EIL). All the organic layers are spin-coated from solution. The device exhibits pure white emission with a maximum luminous efficiency of 9.2 cd A−1 and Commission Internationale d'Eclairage Coordinates of (0.35, 0.36). PFN acting as the EIL material plays a key role in the improvement of the device performance when used in solution-processed small-molecule WOLEDs.