Alginate is the most common used material because it is easy to use, affordable, and well accepted by patients. When impressing, alginate would be in contact with the surface of the oral cavity and saliva. It caused the microflora, like Candida albicanswould adhere to the surface so that it can cause cross-infection. Cross-infection prevention could be done by disinfecting the impression material before filling with gypsum. The main things of choosing a disinfectant is that the disinfectant material could eliminate microorganisms and affect the dimensional stability of impression material. This study aimed to determine the effect of alginate impression disinfection with sodium hypochlorite and castor oil (Ricinus communis oil) on the Candida albicanscounts and the dimensional stability of the study model. The samples of Candida albicanswas counted by colony counter andthe dimensional stability test by digital caliper. This study showed that alginate impression desinfection with castor oil had almost the same effectiveness as sodium hypochlorite in reducing the Candida albicanscounts, but dimension was changed even though the value of the dimensional changes is still within the tolerance limit.