Ceria-silica composite nanoparticles are used in a variety of areas including catalysis, biomedical applications, and the microelectronic industry. In this study, we explain the connection between colloidal forces of interaction during preparation of ceria-silica mixed colloidal particles, the stability of these suspensions, and the relationship between the stability and the functionality of mixed colloidal particles under different conditions. Short-term stability evolution of the mixed colloidal particles reveals that at the very early stages of the interaction of ceria and silica, the interaction rate increases until it reaches a maximum value, and then it decreases during the subsequent stage. More importantly, it is found that the first stage of the interaction becomes more dominant at lower relative surface area of ceria to silica. Derjaguin-Landau-Verwey-Overbeek theory of colloidal interaction is successfully used to explain short-term stability results. Moreover, it is found that mixed colloidal particles exhibit a long-term stability behaviour that not only depends on the colloidal forces of interaction between ceria and silica particles, but also is affected by hydrodynamic effects such as gravitational forces. For that reason, mixed colloidal particles exhibit long-term stability behaviours that are not the same as their short-term stability. (C) 2016 Elsevier B.V. All rights reserved.