Introduction: to evaluate Kaiser Score's diagnostic efficacy and inter-reader reliability and contrast it with the typical BI-RADS Lexicon.Materials and methods: This retrospective study included 100 participants with a total of 109 breast lesions, at Assiut University hospital in the period from January 2021 to June 2021. The fifth edition of the MRI BI-RADS Lexicon was used to determine the BI-RADS category for each lesion after two radiologists reviewed all MRI scans. Following the flowchart for the Kaiser Score, they were then categorized according to BI-RADS category assignments. Finally, a comparison of the Kaiser BI-RADS and score results with the MRI BI-RADS and histological data was made to assess the diagnostic accuracy and inter-observer agreement. Results: There was no noticeable difference between the Kaiser score and the BI-RADS, MRI BI-RADS, or the BI-RADS as the p-values for the diagnosis of all breast lesions, whether mass or NMEL, were 0.597, 0.84, and 0.495 respectively. The inter-observer agreement between Readers 1 and 2 in the diagnosis of all breast lesions, regardless of whether they were mass lesions or NMELs, using both Kaiser BI-RADS and MRI BI-RADS, was also significantly higher since the p-value was less than 0.001. Conclusion: Kaiser score and MRI BI-RADS can be combined to enhance reader agreement and reduce experience-related variability. For readers with less experience, it can also be very helpful in making the diagnosis of doubtful and suspicious breast lesions.