To evaluate the effect of sodium hypochlorite (NaOCl) on biofilms, colour stability (ΔE) and surface roughness (Ra) of complete dentures and patient acceptability. Denture cleansers should be able to reduce the accumulation of biofilms without affecting the acrylic resin properties. Patient satisfaction is important to maintaining their daily use. Fifteen participants were instructed to keep their dentures immersed daily in a 0.5% NaOCl solution for 3 min over 90 days. Swabs were taken from dentures and inoculated on CHROMagar and blood agar. The number of colony-forming units (cfu) was counted after a 48-h incubation period. ΔE was assessed using the CIE L*a*b* system. Ra was measured using a profilometer. Patient acceptability was checked based on their degree of satisfaction. Cell counts, ΔE and Ra were analysed using anova, Friedman's and Kruskal-Wallis tests, respectively (α = 0.05). A significant reduction in the total number of microorganisms (p = 0.001) and Candida spp. was noticed. No significant differences were found for ΔE (p = 0.68) and for Ra (p = 0.47). The level of the patient satisfaction increased throughout the follow-up period. The 0.5% NaOCl solution was effective in reducing microorganisms without significant changes in colour or roughness of denture resin. The participants reported satisfaction with the cleaning results.