OBJECTIVE: Flexural strength, diametral tensile strength, and hardness of a glass ionomer cement containing nano-titanium dioxide and chitosan were determined. MATERIAL AND METHODS: This study analyzed a total of 216 samples. The samples were classified into six major categories, including Group 1 (non-modified GICs as a control group), Group 2 (3 wt% nanotitanium incorporated GIC powder), Group 3 (5 wt% nanotitanium incorporated GIC powder), Group 4 (3 wt% nanotitanium incorporated GIC powder and chitosan 10 v/v% incorporated GIC liquid), Group 5 (5 wt% nanotitanium incorporated GIC powder and chitosan 10 v/v% incorporated GIC liquid) and Group 6 ( 10 v/v% chitosan modified GIC liquid without any modification in the powder). According to the testing method, each main group was broken into three subgroups (n= 12). Flexural strength, diametral tensile strength, and hardness of modified glass ionomer cement were determined. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey's analysis. At a level of probability of 0.05, statistical significance is achieved. RESULTS: (Group 5) exhibited the highest statistically significant flexural and diametral tensile strength means values, while the control group (Group 1) recorded the lowest strength mean values. However, The results revealed that (Group 3) showed the highest statistically significant surface hardness mean value compared to the dual modification of GIC, non-modified GIC, and the chitosan-modified GIC. CONCLUSION: The addition of TiO2 nanoparticles or chitosan to GIC boosts its flexural and diametral tensile strengths, and the optimum improvement will be obtained with the dual modification.