In this study, the effectiveness of Professional Lysol (PL) disinfectant in both its spray and solution forms was evaluated as a surface disinfectant for irreversible hydrocolloid (IH) impressions. Sixteen impressions of a typodont were made with IH, immersed in a microbial broth, and then rinsed in running tap water. The impressions were then treated as follows: four were immersed in PL for 2.5 minutes; four were sprayed by PL and stored for 10 minutes; four were immersed in 2% glutaraldehyde for 10 minutes; four were untreated. Pretest plates showed an average of 421 colonies per plate (c/p). The glutaraldehyde group showed 0.00 c/p. The PL spray group showed 1.75 c/p. The PL immersion group showed 19.00 c/p and showed evidence of surface deterioration in the IH. The untreated group showed 426.25 c/p.