This study examined the compatibility of nine popular gypsum products with three more recently developed irreversible hydrocolloid impression materials, some of which were disinfected before pouring. A test die and evaluation procedure conforming to ANSI/ADA specification no. 18 standards were used to evaluate detail reproduction of the impression materials and detail transfer and roughness of the resultant die. Statistical evaluation of the data revealed that there continue to be deleterious surface interactions between specific irreversible hydrocolloid materials and gypsum products. Analysis also confirmed that the phenolic disinfectant used in this study did not influence the surface interaction between materials nor alter the resultant dimensional properties of the gypsums used.