Oral candidiasis is an opportunistic infection of the oral cavity. This study aimed to determine prevalence of oral candidiasis in patients with palatal coverage orthodontic appliances and prostheses and its risk factors. Three groups of patients were recruited after an informed consent. The two tested groups were the denture and the upper removable orthodontic appliance (URA) groups while patients with no prosthesis/appliance acted as control. The assessments included demographic profile, denture/URA age, night-time wearing and duration of wearing. Signs and symptoms of candidiasis were examined intra-orally. Unstimulated salivary flow rate test was also performed. Smears samples were taken from palatal mucosa and impression surfaces of denture/URA and stained with Periodic Acid Schiff (PAS). The data were analysed using descriptive and chi-square tests. A total of 86 patients were recruited; denture (n=30), URA (n=22), control (n=34). Denture and URA groups had significantly more positive cases of candidal infection (56.7 and 72.7% respectively) as compared to control group (20.6%). Among the subjects with oral candidiasis, denture patients were detected to have more severe amount of candidal hyphae (20%) than URA (13.6%) group. The relationships between oral candidiasis and these risk factors i.e. age, night-time wearing, daily total hours of wearing and denture/URA hygiene were statistically significant (p