Statement of problem In the outbreak of Covid-19, coinfections and even superinfections in the background of SARS-CoV-2 viral infection have been reported. Such bacterial and fungal strains may be colonized in different tissues and organs, including the oral cavity. Whether infection with Covid-19 could increase colonization of different bacterial strains on removable dental prostheses is unclear. Purpose The purpose of this clinical study was to compare bacterial colonization on removable dental prostheses in patients with Covid-19. Material and methods Two sex- and age-matched groups of complete-denture wearing participants (N=60) with and without a positive diagnosis for Covid-19 were enrolled in the study. Swabs were used at 2 different time intervals to sample areas of the dentures, which were then cultured and the colony smears Gram stained. Statistical analysis was conducted by using the Mann U Whitney test (α=.05). Results Streptococcus species (93.3% versus 40.0%, P =.047) and Klebsiella pneumonia (46.7% versus 13.4%, P =.036) were detected more frequently in the Covid-19 positive group. Conclusions Higher rates of bacterial colonization, especially with Streptococcus species and Klebsiella pneumonia, were detected on removable dental prostheses after Covid-19 infection.