Introduction: The caries process is characterized as a lifetime disease that occurs at an early phase of life. One of the most important factors which influence the development of dental caries is saliva. Aim of the study: The study was conducted to correlate the effect of ageing on selected physical properties of saliva and caries experience. Methodology: A cross-sectional comparative research was assessed among 90 healthy subjects (males only) who attended International Medical Center at Baghdad city. They were classified into 3 age groups (20 years, 40 years and 60 years) each age groups consisted of 30 subjects. The data was then statistically analyzed using SPSS version 22. Statistically, a significant difference was at p<0.05. Results: The current study found that the increase in the mean value of caries experience represented by DMFs with an increase in age (7.27 ± 8.02), (22.07 ± 20.33), (60.37 ± 31.39) respectively. There was a highly statistically significant difference between different age groups (p<0.01). The present study recorded decrease in the mean value of salivary flow rate and a slight increase in the mean value of salivary viscosity with an increase in the age with highly significant difference (p<0.5) among different age groups, while salivary pH recorded approximately equal mean value with no significant difference among different age groups. The current study revealed a negative significant correlation between Ds fraction with salivary PH among the young age group, a positive correlation was recorded between (Ds) fraction with salivary viscosity among young and middle-aged groups. Conclusion: The present data suggest that with increasing age an increase in dental caries is experienced. There are significant age-related differences in salivary physical properties that can affect the caries experience.