Demulsification of water-in-diluted bitumen froth emulsions is greatly affected by the presence of solids in the emulsions. In this paper, the wettability, composition, and particle size distribution of the solids extracted from bitumen froth emulsions and diluted bitumen after demulsification, in the absence and presence of a demulsifier, were investigated using partitioning tests, X-ray diffraction, and scanning electron microscopy. It was found that the application of the demulsifier assisted in the removal of water-wet solids, with the main components of the solids in the diluted bitumen being siderite and clays. The median particle size of the solids (D-50) was reduced from 8 mu m in the bitumen froth emulsions to less than 2 mu m in the diluted bitumen phase after the use of a demulsifier in the diluted bitumen froth treatment. The presence of fine solids in the diluted bitumen froth increased the water/bitumen interfacial tension and increased the difficulty of demulsification because the fines are biwettable and adsorb strongly at the water/bitumen interface. The effect of solids on diluent loss to the settled water and solids phase after demulsification was also studied using model emulsions. The diluent loss was found to increase with the solids content of the emulsions. At the same solids content and composition, the diluent losses increased with the fine solids content of the solids. The application of the demulsifier led to a greater diluent loss, and the loss increased with the demulsifier dosage. The results from the diluent loss studies revealed that diluent loss is caused by the adsorption of diluent on the solids. The target of demulsification of water-in-diluted bitumen froth emulsions is to achieve clean and dry diluted bitumen (<1.5% water and <0.6% solids) and to keep the bitumen/diluent losses to the settled water and solids phase minimized. In addition to dewatering, the demulsifiers must change the wettability of the solids and/or disperse the bitumen/solids aggregates to reach lower bitumen/diluent losses and keep a higher water and solids removal efficiency in the demulsification of water-in-diluted bitumen froth emulsions.