Purpose: To assess the role of toothbrushing self-efficacy (TBSE) in toothbrushing (TB) behaviour and diabetes management, measured in terms of HbA1c knowledge, quality of life, BMI, self-reported health and physical activity among Turkish type-II-diabetes (DM2) patients. Materials and Methods: A pilot study using self-administered health questionnaires was conducted among a random sample of 60 patients (aged 40 to 70 years) in Istanbul, Turkey. The assessed variables were: TBSE, TB, glycated haemoglobin (HbA1c) knowledge, quality of life, BMI, self-reported health and physical activity. Descriptive statistics, frequency distributions, Pearson's correlation, the chi-square test and MANOVA were applied. Results: Almost half of the patients reported low TBSE (mean >= 53%). and TB once a day (54%). Most (77%) did not know their HA1C level and they were overweight (42%) and obese (32%). Almost half of the patients reported good quality of life (> mean, 55%), being physically active (51%) and in good health (mean 46%). The patients reporting high levels of TBSE were more likely to know their HbA1c (OR = 10.5: 95%CI = 1.01-103.24) and to report better health (OR = 10.0: 95%CI = 1.80-55.63) and were less likely to be obese (OR = 0.16: 95%CI = 0.02-1.00) (P 0.05). There was a strong correlation between TBSE and TB (rs = 0.61, P 0.01). Conclusion: The present study underlines the need for TBSE-integrated common health promotion for oral health and DM2, considering the relation of TBSE, HbA1c, BMI and toothbrushing. Keywords: BMI (body mass index), diabetes management, oral health behaviour, self-efficacy, WHOQOL-Bref