Aim: to investigate: The dental caries experience during mixed dentition, the salivary flow rate, the pH of saliva, the microbiological count of salivary Streptococcus Mutans and cariogenic Lactobacilli; In a group of asthmatic Egyptian children. Methods: Study sample of 2 groups each (n=30) group 1; Asthmatic children with mixed dentition (6-12 years) was collected from Abu elreesh hospital, faculty of Medicine, Cairo University, the asthmatic group was classified according to the severity of asthma, inhaled medicaction and the use of spacer. Group 2; An age and sex matched control group was selected (free from any medical condition) from out-patient clinic of Pediatric and Community Dentistry Department, faculty of Oral and Dental Medicine, Cairo University, both groups were evaluated for dental caries experience using (deft) & (DMFT) caries indices, salivary samples were collected to:(1) Measure salivary flow rate, (2) Measure salivary pH, (3) Measure salivary Streptococcus mutans and cariogenic Lactobacilli. Results; mean DMFT+deft in asthmatic group and control group was 3.73±1.08 & 2.07±0.69 respectively, mean salivary flow rate in asthmatic group and control group was 0.451±0.2 ml/min & 0.969±0.13 ml/min, respectively, mean salivary pH in asthmatic group and control group was 6.84±0.86 & 7.92±0.63 respectively, mean salivary SM count in asthmatic group and control group was 90.2±28.8 cfu & 5.30±1.49 cfu, respectively, mean salivary Lb count in asthmatic group and control group was 17.46±6.16 cfu & 2.73±1.31 cfu. Respectively Conclusion; Asthmatic children had a higher caries experience, lower salivary flow pH, flow rate and higher count of cariogenic micro-organisms than in the healthy children.