<i>Objective</i>: The aim of this study was to evaluate the difference in caries experience and different caries-related variables between diabetic and non-diabetic children aged 5-13 years old. A further analysis was carried out on diabetic children after they were divided in two groups based on their metabolic control.<br/> <i>Material and Methods</i>: We designed a case-control study on two categories of children: the first group consisted of 68 children diagnosed with type 1 diabetes and the second group consisted of 136 non-diabetic control children. The diabetic children were then divided into two subgroups: a) 20 children with adequate metabolic control (Hb1ac≤7.5) and b) 48 children with poor metabolic control (Hb1ac&gt;7.5). Data on dietary and oral hygienic habits was obtained on all the subjects participating in the study. Collection of saliva was carried out after stimulating salivation by chewing on a piece of paraffin for 5 minutes. Microbial flora was analyzed using the checkerboard DNA-DNA hybridisation method. Plaque acidogenity was recorded using pH indicator strips up to 30 min after a sucrose rinse. Caries registration was performed using the ICDAS index.<br/> <i>Results</i>: No statically significant difference in clinical data was found in the two study groups with similar caries status. No statistically significant difference was found for tooth brushing frequency, use of fluoridated toothpaste, mouthwash and other fluoride supplements and the pattern of dental check-ups between the groups examined. Statistically significant differences for plaque-pH when analyzed as minimum pH, AUC_6.2 and AUC_5.7 between all diabetic and the non-diabetic children (p&lt;0.01 or p&lt;0.05) were found. The bacterial counts differed significantly between diabetic and non-diabetic subjects regarding <i>S. Mutans, S. Sobrinus, L. Salivarius</i> and <i>L. Fermentum</i> (p&lt;0.05).<br/> <i>Conclusions</i>: Type 1 Diabetes Mellitus patients showed a more cariogenic bacterial environment and a direct effect on plaque pH reducing it from normal levels was detected.